A  READER  IN  PHYSICAL  GEOGRAPHY 
FOR  BEGINNERS 


A   READER 


IN 


PHYSICAL  GEOGRAPHY 


FOR  BEGINNERS 


BY 

RICHARD    ELWOOD   DODGE 

PROFESSOR  OF  GEOGRAPHY,  TEACHERS  COLLEGE,  COLUMBIA  UNIVERSITY, 

CO-EDITOR  OF  'THE  JOURNAL  OF  GEOGRAPHY,'  AUTHOR  OF 

4  DODGE'S  SCHOOL  GEOGRAPHIES,'  ETC. 


LONGMANS,    GREEN,   AND    CO. 

FOURTH   AVENUE  &  30TH  STREET,  NEW  YORK 
LONDON,   BOMBAY  AND  CALCUTTA 


COPYRIGHT,  1900,  BY 
LONGMANS,  GREEN,  &  CO, 


Fir<t  rrlicion,  November,  1900 
Reprinted  (revised),  October,  1901;  August,  igo2 

Fe-brtiury.,  19*03;.  Jttly,  1904 
vX-t»Ver/.:gos;  Jnl}',  1911 


PREFACE. 

THIS  little  book  has  been  written  with  the  thought 
chat  hitherto  no  one  volume  has  been  available  in  which 
the  more  important  principles  of  Physical  Geography 
have  been  brought  together  in  a  form  to  be  used  by 
beginners  in  the  subject.  The  demand  for  such  a  treat- 
ment of  Physical  Geography  grows  larger  daily,  and  in 
attempting  to  meet  that  demand  the  author  has  aimed  to 
adapt  the  subject-matter  to  the  needs,  the  abilities,  and 
the  interests  of  youthful  readers.  For  that  reason  much 
attention  has  been  given  to  human  and  other  life  con- 
ditions, in  so  far  as  they  are  dependent  upon,  or  deter- 
mined by,  the  physical  features  of  the  world. 

Although  it  is  believed  that  the  facts  are  accurate  as 
stated,  and  the  generalizations  tenable,  there  has  been 
no  attempt  to  write  a  complete  text-book  in  Physical 
Geography.  The  thought  has  been  rather  to  write  a 
suggestive  book  that  would  leave  the  reader  with  a  desire 
to  go  further  and  find  more.  Partly  for  that  reason,  and 
partly  to  give  training  in  seeking  information  in  other 
sources,  no  attention  has  been  given  to  summaries  of  the 
physical  features  of  the  several  continents.  It  is  hoped 
that  the  book  may  be  used  as  a  reader  in  association  with 
a  text-book,  and  that  details  in  reference  to  special  topics 
will  be  sought  under  the  description  of  the  continents  in 
such  text-books,  and,  further,  that  an  atlas  may  con- 
stantly be  used  iit  connection  with  the  book.  Long- 

266657 


vi  PREFACE. 

mans'  New  School  Atlas  is  recommended  as  being  in 
many  ways  the  most  serviceable ;  but  the  maps  accom- 
panying our  better  school  geographies  will  well  serve  the 
needed  purpose. 

The  illustrations  are  very  largely  from  original  photo- 
graphs by  the  author,  and  have  been  chosen  for  their 
geographical  value  rather  than  as  mere  pictures.  As  far 
as  possible  diagrams  have  been  avoided.  Certain  cour- 
tesies in  reference  to  the  illustrations  are  noted  in  the 
text.  The  author  has  also  received  permission  to  use 
original  photographs  from  many  sources,  and  is  espe- 
cially indebted  to  several  of  his  colleagues  in  the  Teachers 
College.  Thanks  fo'r  assistance  in  reference  to  illustra- 
tions is  also  cordially  given  to  the  following:  The  United 
States  Geological  Survey,  The  Maryland  Geological  Sur- 
vey, The  New  York  Zoological  Garden,  The  Hyde  Ex- 
ploring Expedition,  Mr.  J.  B.  Woodworth  of  Harvard 
University,  Mr.  G.  H.  Barton  of  the  Massachusetts 
Institute  of  Technology,  and  Mr.  J.  T.  McDonald  of 
Delhi,  New  York. 

Miss  Caroline  W.  Hotchkiss  and  Miss  Clara  B.  Kirch- 
wey,  instructors  in  the  Horace  Mann  School  of  Teachers 
College,  have  offered  many  valuable  suggestions  in  refer- 
ence to  the  text,  and  Miss  Mabel  K.  Myers  has  prepared 
the  index  and  assisted  with  the  proofs. 

RICHARD  E.  DODGE. 

OCTOBER,   1900. 


CONTENTS 


CHAPTER  PAGE 

I.     THE  WORLD  AS  A  WHOLE  .......        i 

Our  Relation  to  the  World  as  a  Whole. 

THE   CONTINENTS 

II.     THE  LARGER  FEATURES  OF  THE  CONTINENTS  10 

Continents  and  Oceans. — Coast  Line.  —  Harbors. — The  Land. — 
Highlands  and  Lowlands. — Relief  and  Altitude. 

III.     THE  LARGER  FEATURES  OF  THE  CONTINENTS — (Continued)       18 

Mountains. — Continents  and  Highlands. — Lowlands. — Greater 
New  York. — Summary. 

THE   INDUSTRIES  OF   MEN 

IV.     CENTRES  OF  INDUSTRY         .......      28 

Importance  of  Work. — Centres  of  Life. 
V.     CENTRES  OF  INDUSTRY — (Continued)    .....       33 

Commercial  Centres. — Agricultural  Centres. — Grazing  Centres. 
—Lumbering  Centres. 

*  VI.     CENTRES  OF  INDUSTRY — (Continued) 47 

Manufacturing  Centres. — Mining  Centres. — Fishing  and  Hunt- 
ing Centres. — Scenic  Centres. — Summary. 

THE   ORIGIN   OF   LAND   FORMS 

VII.     CHANGES  IN  THE  EARTH'S  CRUST 59 

Permanency  of  Land  Forms. — The  Materials   of   the    Earth's 
Crust. — Strong  and  Weak  Rocks. — How  the  Earth  Wears  Away. 

VIII.     THE  WORK  OF  THE  ATMOSPHERE 69 

Weathering.— The   Effects   of  Gravity.— Talus   Slopes.— The 
Wind. — Dunes, 


Vlll  CONTENTS. 

CHAPTER  PAGE 

IX.    THE  WORK  OF  RUNNING  WATER 81 

The  Erosive  Work  of  Running  Water. — The  Deposits  of  Run- 
ning Water. — Alluvial  Plains. — Alluvial  Fans. — Deltas. — Rapids 
and  Waterfalls. — Results  of  Work  of  Running  Water. 

X.     THE  WORK  OF  STANDING  WATER 100 

Kinds  of  Standing  Water. — Wave  Erosion. — Wave  Deposits. — 
Ocean  Currents. — Tides. — Lakes. — Summary. 

XI.     THE  WORK  OF  ICE  AND  FROST  .        .        .        .        .119 

Effect  on  Life. — Effect  on  Rocks. — Snow. — Glaciers. — Re- 
view.— Erosive  Work  of  Ice. — Transportation  Work  of  Ice. — 
Deposits  Made  by  Ice.— The  Work  of  the  Great  Ice  Sheet.— 
Summary. 

THE   GREAT   LAND    FORMS 

XII.     PLAINS  AND  PLATEAUS          ....  .        .     137 

Plains. — Plateaus. 

XIII.  MOUNTAINS 144 

Mountain  Building. — Causes  of  Mountains. — Kinds  of  Moun- 
tains.— Aging  of  Mountains. 

XIV.  VOLCANOES 154 

Shape  of  Volcanoes. — Kinds  of  Volcanoes. — Aging  of  Vol- 
canoes.— Earthquakes. — Geysers  and  Hot  Springs. 

XV.     MOVEMENTS  OF  THE  LAND 1*65 

Coast  Lines. — Drowned  Valleys. 


CLIMATE 

XVI.  WHAT  is  WEATHER  AND  CLIMATE?    .....     171 
Weather  and  Climate. 

XVII.  TEMPERATURE      .        .        .        .        .        .        .        .        .176 

Measurement    of    Temperature. — Source    of    Earth    Heat. — 

The  Motions  of  the  Earth.— Zones  and  Heat  Belts. 


CONTENTS.  IX 

CHAPTER  PAGE 

XVIII.    WINDS  AND  RAINFALL l85 

Moisture  and  Rainfall.— Deserts  and  Arid  Regions.— Rainfall 
of  the  World. 

XIX.    CLIMATE  OF  THE  WORLD *94 

Seasons. — Summary. 


OTHER     IMPORTANT    PHYSICAL     FEATURES 
INFLUENCING   MAN 

XX.     SOILS •        .    •    .     198 

Kinds  of  Soils.— Fertility  of  Soils. 

XXI.     WATER  SUPPLY          . 2o6 

Springs  and  Wells. 

XXII.     DEFENCE  AND  NATURAL  PRODUCTS  ....     213 

Natural  Products. 

XXIII.  TRANSPORTATION  AND  POWER 222 

Power. 

XXIV.  SUMMARY „        .     228 

The  Historical  Distribution  of  Peoples. 


A  READER 
IN    PHYSICAL    GEOGRAPHY. 

CHAPTER   I. 
THE   WORLD   AS   A   WHOLE. 

EVERY  one  knows  something  about  geography,  though 
he  may  not  have  learned  it  from  books  and  atlases,  and 
makes  some  use  of  his  knowledge  in  every-day  life. 
The  city  boy  follows  a  certain  route  between  school  and 
home,  because  the  city  has  been  planned  so  that  the 
main  streets  avoid  the  steep  slopes,  and  because  the 
school-house  has  been  built  where  it  would  be  easily 
reached  by  a  large  number  of  pupils.  The  country  boy 
knows  where  to  find  the  springs  and  the  swimming  pools 
in  the  brooks,  and  can  tell  you  what  sort  of  land  is  the 
best  for  certain  crops.  He  makes  his  way  across  the  coun- 
try without  paying  attention  to  the  roads,  because  he 
knows  the  geography  of  the  whole  region  thoroughly,  and 
perhaps  could  make  a  map  of  it  with  his  eyes  shut.  He 
knows  its  geography  from  personal  study  of  the  land 
itself,  and  not  from  having  read  about  it  in  books.  The 
Indian  of  the  great  plains  of  the  West  follows  the  easiest 
and  best  route  between  one  place  and  another  across  the 
so-called  "  trackless  waste,"  because  he  knows  the  rela- 
tive position  of  every  peak  and  valley,  and  is  as  much 
accustomed  to  finding  his  way  by  seeking  out  certain 


2  A  READER  IN  PHYSICAL  GEOGRAPHY. 

landmarks  as  the  city  boy  is  by  noting  the  buildings  and 
the  familiar  street  corners. 

No  one  who  is  interested  in  what  is  going  on  in  the 
world  can  fail  to  be  interested  in  geography,  for  it  is  only 
through  his  knowledge  of  the  geography  of  a  region  that 
he  can  understand  what  men  are  doing  there,  and  why  they 
are  living  and  acting  in  certain  ways.  Nearly  every  spring 
we  read  of  destructive  windstorms  or  tornadoes  in  some 
of  our  Central  States,  particularly  in  Missouri  or  Kansas. 
The  storms  are  of  special  interest  because  of  their  vio- 
lence and  destructive  nature,  yet  we  cannot  understand 
such  storms  unless  we  know  something  more  about  them 
than  their  location.  We  must  know  what  causes  such 
winds  at  certain  seasons,  and  why  these  prairie  States 
seem  to  be  the  regions  where  such  storms  are  the  worst. 
In  such  a  little  thing  as  this  we  have  to  study  the  con- 
ditions of  the  air  that  cause  the  winds,  the  character  of 
the  land  over  which  the  winds  move,  and  the  effects  on 
men  and  all  living  things.  We  are  here  studying  some 
of  the  forces  of  nature  at  work,  but  all  the  facts  are 
geographical. 

But  it  would  be  a  mistake  to  suppose  that  geography 
is  a  study  of  the  earth  and  of  natural  forces  only.  An 
important  and  interesting^  part  of  geography  deals  with 
the  people  of  the  earth,  how  they  live,  what  they  do  for 
a  living,  and  why  they'have  chosen  to  dwell  just  where 
they  do  instead  of  elsewhere.  Geography  helps  us  to 
understand  the  people,  as  well  as  the  places,  climate,  and 
natural  features  of  the  earth.  We  are  sometimes  amused 
at  the  customs  of  strange  people  who  live  in  foreign  lands, 
just  as  we  may  be  at  the  queer  ways  of  our  neighbors, 
and  forget  that  these  other  people  are  just  as  likely  to 
think  us  queer  as  we  are  to  think  them  queer,  and  that 


THE  WORLD   AS  A  WHOLE.  3 

they  have  the  same  right  to  be  amused  at  us  as  we  have 
to  be  amused  at  them.  We  would  not  be  so  amused  did 
we  realize  that  people  living  amid  conditions  different 
from  those  around  us  cannot  live  as  we  live.  A  farmer 
accustomed  to  take  his  time  to  reach  home  after  his 
day's  work  might  open  his  eyes  in  wonder  at  the  way 
people  in  large  cities  rush  and  crowd  to  get  seats  on 
ferry-boats  or  on  trains,  and  think  them  very  foolish  to 
waste  so  much  energy.  If  he  were  to  come  away  from 
the  quiet  of  his  farm  and  live  in  a  city,  he  might  soon  be 
rushing  about,  seemingly  as  crazy  as  all  his  neighbors. 
In  the  same  way  we  may  think  it  curious  that  many 
Indians  live  in  movable  tents  or  tepees  rather  than  in 
permanent  houses;  but  we  would  soon  find  out,  were 
we  to  try  to  live  in  the  Indian  country  according  to  our 
civilized  customs,  that  the  Indian  knows  better  than  we 
how  to  be  comfortable  and  healthy  in  his  home  on  the 
plains.  Such  are  a  few  of  the  features  of  the  world  that 
are  readily  understood  as  soon  as  we  know  the  geography 
of  the  regions  in  which  they  occur. 

The  world  is  so  large,  and  the  facts  to  be  known  about 
it  and  its  inhabitants  are  so  many  and  varied,  that  it  is 
not  possible  for  us  to  study  the  whole  field  in  detail. 
But  geographical  facts  are,  after  all,  very  much  alike 
the  world  over.  And  we  shall  find  that  if  we  study 
carefully  our  own  home  locality,  we  shall  have,  as  it  were, 
a  key  to  the  understanding  of  every  other  region.  Our 
very  coldest  winter  days  help  us  to  realize  the  kind  of 
weather  the  Eskimo  endures  most  of  the  time,  and  a  hot, 
muggy  day  in  summer,  when  we  feel  lazy  and  want  to  do 
nothing  but  try  to  keep  cool,  makes  us  understand  why 
the  black  man  of  Central  Africa  is  neither  energetic  nor 
enterprising.  Again,  we  know  by  looking  about  us  that; 


4  A  READER   IN   PHYSICAL  GEOGRAPHY. 

every  part  of  the  city  or  district  in  which  we  live  is  not 
equally  desirable  for  homes,  and  that  there  are  some 
places  that  are  not  occupied  at  all.  This  fact  may  help 
us  to  understand  why  it  is  that  there  are  portions  of  the 
world  where,  either  because  the  slopes  are  too  steep  or 
because  the  soil  is  barren,  or  for  some  like  reason,  no  one 
cares  to  live,  or,  indeed,  can  live. 

Thus  by  observing  the  geographical  conditions  close  at 
hand  we  are  prepared  to  appreciate  those  at  a  distance. 
If,  however,  we  are  to  use  these  home  conditions  as  keys 
or  measures  in  this  way,  we  must  first  come  to  know 
thoroughly  our  own  surroundings.  This  does  not  mean 
that  we  must  study  our  own  town  or  city  or  State  as  a 
thing  by  itself,  with  no  thought  of  its  relation  to  the  rest 
of  the  world,  of  which  it  is  but  a  small  part;  for  that 
would  be  much  like  thinking  that  one  grape,  taken  by 
chance  from  a  bunch,  gave  us  the  right  idea  of  the  whole 
bunch  or  of  all  the  bunches  on  the  vine.  •  Before,  there- 
fore, we  look  at  the  small  details  of  the  geography  about 
us,  let  us  see  some  of  the  things  there  are  in  the  world 
which  affect  us  just  as  they  affect  all  men  the  world  over. 

Our  Relation  to  the  World  as  a  Whole. — The  world 
as  a  whole  is  made  up  of  land,  water,  and  air;  and  of 
these  the  great  bodies  of  land  are  the  most  important  to 
us,  for  we  live  on  and  travel  over  the  land,  and  get  from 
it,  either  directly  or  indirectly,  nearly  all  those  materials 
that  furnish  us  food,  clothing,  and  shelter — the  three 
things  that  we  must  have  in  order  to  live.  It  is  true  that 
there  are  places  in  the  world  where  men  may  go  beneath 
the  surface  of  the  earth  a  very  slight  distance,  in  mines 
or  in  railway  tunnels;  but  their  stay,  as  a  usual  thing,  is 
very  short.  The  longest  railway  tunnel  can  be  passed 
through  in  a  few  minutes,  and  most  miners  have  their 


THE  WORLD  AS  A  WHOLE.  5 

homes  on  the  surface  of  the  earth,  though  they  may  stay 
several  hours  a  day  underground.  Hence  we  can  truth- 
fully say  that  the  vast  majority  of  men  live  on  the  very 
surface  of  the  land,  and  have  but  little  to  do  with  any 
other  part  of  it.  Indeed,  we  may  almost  say  that  man 
has  never  descended  into  the  earth  *  a  distance  far 
enough  to  be  thought  of  as  being  below  the  surface  at 
all,  for  the  deepest  mine  only  penetrates  the  earth  about 
a  mile,  and  it  is  about  four  thousand  miles  to  the  centre 
of  the  earth. 

In  the  same  way,  we  have  but  little  to  do  with  other 
than  the  surfaces  of  the  rivers,  lakes,  and  oceans  of  the 
world.  We  sail  over  the  water  of  the  oceans  and  large 
rivers  and  lakes  with  almost  equal  ease  in  any  direction, 
and  except  in  the  case  of  deep-sea  fishing,  men  are  but 
little  concerned  in  their  daily  life  with  any  other  parts 
of  the  waters  of  the  world  than  the  ever-moving  and 
ever-changing  surface. 

When  we  think  of  the  air,  however,  it  is  far  different ; 
for  we  live  at  the  bottom  of  the  atmosphere,  and  are 
related  to  it  very  much  as  a  fish  in  the  deep  sea  is  related 
to  the  waters  of  the  ocean.  Occasionally  men  do  rise 
into  the  air  for  a  short  distance  in  balloons,  but  they 
have  not  learned  how  to  travel  through  the  air  or  how  to 
live  in  it,  except  at  the  bottom.  The  most  hazardous 
voyages  in  balloons  have  carried  men  but  little  farther 
above  the  earth  than  mines  go  into  it,  and  even  birds 
that  leave  the  solid  earth,  and  remain  poised  above  our 
heads  for  hours  at  a  time,  can  reach  but  a  limited  height ; 

*  The  word  earth  is  sometimes  used  to  refer  to  the  whole  globe  on  which 
we  live,  and  sometimes  to  the  solid  or  rock  part  of  that  globe.  It  will  be 
used  in  the  latter  sense  here,  and  world  will  be  used  when  we  refer  to  the 
whole  globe. 


0  A   READER  IN   PHYSICAL  GEOGRAPHY. 

they,  like  people  and  animals  who  stay  on  the  ground, 
are  really  at  the  bottom  of  the  great  ocean  of  air  that 
stretches  above  the  world  for  an  unknown  distance. 

Beneath  the  oceans,  as  well  as  beneath  the  continents, 
are  the  solid  rocks  of  the  earth,  that  form  the  central 
core  of  the  world — the  foundation  on  which  all  else  rests. 
This  arrangement  is  just  what  we  would  expect;  for  the 
solid  earth  is  at  the  bottom,  the  liquid  water  is  next 
above,  and  the  invisible,  gaseous  atmosphere  is  over  all, 
the  three  great  parts  of  the  world  being  thus  arranged  in 
the  order  of  their  weight.  Yet  these  three  divisions  of 
the  world  are  not  absolutely  separated,  for  the  rocks  and 
soils  of  the  surface  of  the  earth  contain  a  great  quantity 
of  water,  which,  creeping  along  underground,  feeds  the 
roots  of  plants.  Whenever  this  water  appears  at  the  sur- 
face, we  have  a  wet  place  or  a  spring,  from  which  water 
may  trickle  in  a  small  stream.  Every  such  spring  or  wet 
place  is  one  of  the  beginnings  of  a  large  river;  but  it 
takes  many,  indeed  hundreds  of  thousands,  of  such  small 
springs  to  make  a  large  river  such  as  the  Mississippi. 

It  is  not,  however,  near  the  surface  of  the  earth  alone 
that  water  occurs  in  the  rocks.  Indeed,  the  deeper  we 
go  into  the  earth,  the  more  water  there  seems  to  be,  as 
any  miner  can  tell  you ;  for  in  some  cases  the  water  runs 
into  the  mines  so  fast  that  large  pumps  have  to  be  used 
night  and  day  to  keep  the  mine  from  filling.  The  holes 
and  cracks  in  the  rocks  of  the  earth  that  are  not  full  of 
water  are  full  of  air,  so  that  we  may  say  that  on  the  land 
the  earth,  air,  and  water  are  thoroughly  mingled. 

In  the  same  way  we  find  a  mingling  of  air  and  earth  in 
the  waters  of  the  oceans,  rivers,  and  lakes.  The  rock 
material  in  the  water  is  easily  seen,  for  most  rivers,  par- 
ticularly after  a  rain,  are  much  discolored  from  the  mud 


THE   WORLD   AS   A   WHOLE.  7 

they  contain.  Indeed,  the  cleanest  rain  water  of  the 
heaviest  storm  contains  rock  material  dissolved,  as  sugar 
may  be  dissolved  in  water  that  seems  clear,  and  there 
is  no  water  absolutely  free  from  rock  impurities  except 
that  which  has  been  artificially  purified  in  some  chemical 
laboratory  or  large  factory. 

Passing  from  the  water  and  earth  to  the  air,  we  find 
again  a  mingling  of  materials  similar  to  that  we  have  seen 
before.  The  air  contains  a  great  deal  of  water,  which  is 
at  times  invisible,  but  at  other  times  perfectly  visible  as 
mist  or  fog.  During  storms  some  of  this  water  or  mois- 
ture falls  to  the  earth,  and  runs  down  the  slopes,  making 
rivers  that  flow  toward  the  oceans.  Even  after  a  heavy 
storm  lasting  several  days,  there  is  still  a  large  amount 
of  moisture  left  in  the  air,  varying  with  the  day  and  the 
part  of  the  world.  The  air  may  be  clear,  apparently; 
but  anything  that  absorbs  moisture  easily,  like  the  wool 
on  the  back  of  a  sheep,  will  feel  damp  to  the  touch, 
showing  that  moisture  is  present.  The  air  in  the  eastern 
United  States  is  most  free  from  moisture  during  a  clear, 
cold  snap  in  winter,  when  the  stars  twinkle,  and  every- 
thing seems  to  crackle  with  dryness. 

The  particles  of  rock  dust  of  a  windy  March  day,  and 
the  dancing  rays  of  the  sunbeams  as  they  stream  across  a 
room  in  a  narrow  path,  tell  us  that  there  is  rock  material 
as  well  as  moisture  in  the  air.  It  is  the  dust  in  the  air 
which  catches  the  rays  of  light  at  sunset  and  gives  us 
much  of  the  beautiful  color  that  we  associate  with  that 
hour  of  the  day.  Thus  we  see  that  the  three  great  divis- 
ions of  the  world  we  have  mentioned  are  anything  but 
independent  and  separate  ;  indeed,  the  mingling  is  so 
complete  that  it  is  hard  to  deal  with  one  of  the  three 
divisions  without  considering  the  others  at  the  same  time. 


8  A  READER  IN   PHYSICAL  GEOGRAPHY. 

For  most  of  us,  however,  the  surface  of  the  earth  is 
our  home ;  the  oceans  are  the  great  wastes  that  separate 
the  continents  and  many  of  the  greater  nations,  but  at 
the  same  time  they  are  the  great  highways  of  commerce 
and  travel  that  bind  distant  peoples  more  closely  to- 
gether; the  air  gives  us  breath  and  power  to  do  work; 
and  the  three  parts  working  together  make  living  possi- 
ble. Yet,  since  the  earth  is  the  home  of  man,  it  is  the 
earth  that  we  shall  study  here  in  the  most  detail,  making 
as  much  use  of  the  facts  of  air  and  water  as  is  necessary 
in  order  to  understand  the  story  of  man's  history  and 
activity  in  the  different  parts  of  the  world. 

It  would  be  a  long  and  tiresome  task,  however,  to  try 
to  study  the  whole  world  with  equal  care.  Indeed,  such 
a  study  would  be  impossible,  for  there  are  many  parts  of 
the  world  concerning  which  so  little  is  known  that  a  de- 
tailed consideration  is  out  of  the  question.  As  we  can- 
not spend  all  our  lives  studying  even  those  parts  that  are 
the  best  known  and  the  most  important,  we  must  save 
time  in  some  way  if  we  are  to  get  any  satisfaction  from 
our  study.  The  best  way  to  save  time  is  to  study  in 
detail,  as  has  been  suggested,  some  few  regions  which 
we  can  use  as  guides  to  the  study  of  other  regions.  For 
instance,  if  the  study  of  New  York  State  shows  us  that 
the  great  railroads  follow  river  valleys,  we  can  express 
that  fact  in  a  simple  way  that  will  be  useful  afterwards, 
and  it  will  not  be  necessary  to  study  every  railroad  in  the 
world  with  equal  care,  for  we  should  be  safe  in  saying 
that,  as  a  rule,  railroads  follow  river  valleys.  If  we 
found  a  case  where  this  did  not  hold  true,  then  we  should 
have  an  exception  to  the  rule,  which  we  could  study  with 
special  care. 

As  we  cannot,  however,  personally  see  all  the  many 


THE   WORLD   AS  A  WHOLE.  9 

parts  of  the  land  surface  of  the  world,  we  must  get  our 
facts  largely  from  the  written  descriptions,  the  pictures, 
the  stories,  and  the  maps  that  have  been  given  us  by 
travellers  who  have  seen  that  which  they  describe.  No 
one  book  can  tell  us  all  that  is  known  concerning  the 
world,  and  small  school  geographies,  which  must  contain 
something  about  all  the  important  parts  of  the  world, 
cannot  be  very  full  and  satisfying  in  reference  to  any  one 
region,  even  our  own  country.  The  word  of  a  traveller 
is  more  interesting  than  that  of  a  text-book,  because  the 
traveller  has  seen  what  he  describes,  while  the  writer  of 
the  book  is  only  quoting,  perhaps,  the  words  of  others. 
A  map,  however,  tells  more  in  a  small  space  than  any 
other  form  of  description,  because  a  few  symbols  like 
those  used  to  represent  mountains  or  rivers  stand  for 
many  details.  The  map  cannot  picture  to  us  all  the 
beauties  of  the  mountains,  or  the  details  of  the  river 
valleys;  but  we  can  see  at  a  glance  their  position  and  re- 
lation, when  it  might  take  us  hours  to  get  the  same  idea 
from  reading.  Even  then  we  should  probably  need  to 
make  a  map  to  see  the  relation  clearly,  just  as  a  stranger 
can  better  understand  our  directions  for  finding  a  certain 
place  in  a  large  city  if  we  show  him  the  location  of  the 
streets  by  a  little  drawing. 


THE   CONTINENTS. 

CHAPTER    II. 

THE   LARGER   FEATURES   OF   THE   CONTINENTS. 

Continents  and  Oceans. — As  we  are  thus  most  inter- 
ested in  the  land  and  water  areas  of  the  world,  let  us  look 
for  a  moment  at  some  of  the  most  striking  things  that  a 
good  map  tells  us  about  these  areas.  A  large  wall  map, 
large  enough  to  be  readily  studied  from  across  the  room, 
will  suit  our  purpose;  but  a  good  globe  is  better,  as  it 
expresses  to  us  the  shape  of  the  continents  and  oceans 
of  the  world,  as  well  as  the  direction  of  one  area  from 
another.  Such  a  map  or  globe  shows  us  readily  that  the 
land  is  distributed  over  the  wrorld  in  masses  of  several 
sizes,  the  largest  and  most  continuous  known  as  conti- 
nents, and  the  smaller  and  more  separated  called  islands. 
The  lowest  parts  of  the  earth  between  the  continents  are 
full  of  salt  water  up  to  a  certain  level  which  we  know  as 
the  "  sea  level  "  ;  indeed,  the  hollows  are  so  full  that  the 
waters  surround  the  continents,  in  some  cases  spilling 
over  the  brim,  as  in  Bering  Strait,  between  Asia  and 
North  America. 

Though  continuous,  the  great  salt-water  area  of  the 
world  is  commonly  divided  into  the  large  oceans,  like  the 
Atlantic  or  Indian,  and  the  smaller  seas,  like  the  Carib- 
bean. In  some  cases,  however,  that  which  we  would 


COAST  LINE.      HARBORS.  II 

expect  to  call  a  sea  is  known  as  a  gulf,  like  the  Gulf  of 
Mexico,  or  a  bay,  like  Hudson  Bay,  so  that  gulf,  bay, 
and  sea  may  be  used  almost  interchangeably,  though  sea 
is  the  most  common  and  the  best  name. 

If,  now,  we  look  at  the  globe  from  a  greater  distance,  as 
from  across  the  room,  we  cannot  help  noticing  that  nearly 
all  of  the  land  is  arranged  about  the  North  Pole  as  a  centre. 
If  we  look  directly  down  on  London,  England,  the  half  of 
the  globe  which  we  see  contains  nearly  all  of  the  land; 
though  the  water  occupies  more  than  three-fourths  of  the 
globe,  the  greater  part  is  in  the  other  half  of  the  world 
from  that  just  noted.  This  long-distance  view  tells  us  at 
once  that  the  greater  areas  on  which  men,  animals,  and 
plants  can  live  are  in  the  northern  half  of  the  wo^ld,  or 
our  hemisphere.  We  should  therefore  expect  the  north- 
ern hemisphere  to  contain,  as  it  does,  the  largest  arid 
most  powerful  nations  of  the  world,  and  to  be  the  mo?t 
important  for  study. 

Coast  Line.  Harbors. — As  our  eye  passes  from  the 
land  to  the  water  or  the  water  to  the  land,  we  cannot 
help  noting  the  line  where  they  meet,  which  we  call  the 
coast  line  or  the  seashore.  The  landsman  who  makes  an 
occasional  trip  to  the  distant  ocean  speaks  of  his  journey 
to  the  seashore  or  perhaps  to  the  beach;  but  the  sailor, 
driven  in  a  storm  before  the  waves  and  wind  toward  an 
unfriendly  and  dangerous  land,  dreads  the  coast,  for  it  is 
the  coast  more  than  the  water  that  he  then  fears. 

The  coast  line  of  a  continent,  however,  deserves  men- 
tion for  other  reasons  than  because  it  shows  the  edge  of 
the  land,  the  inner  margin  of  the  sea.  If  a  country  is  to 
have  a  profitable  foreign  commerce,  it  must  be  well  pro- 
vided with  good  harbors.  A  country  with  a  regular, 
unbroken  shore,  such  as  that  of  New  Jersey  and  our 


12 


A  READER  IN   PHYSICAL  GEOGRAPHY. 


Southern  Atlantic  States,  or  that  of  Africa  and  western 
France,  has  but  few  inlets.  Such  a  country  offers  vessels 
no  chance  to  find  protected  anchorage  in  time  of  storm, 
and  no  good  landings  for  loading  or  unloading,  and  hence 
cannot  have  many  large  commercial  cities  along  its  coast. 
Such  dangerous  coasts  are  usually  provided  with  life-sav- 
ing stations,  where  men  are  continually  on  the  watch  to 
offer  assistance  in  case  of  a  wreck.  (See  Fig.  i.) 


Copyright  by  Perry  Picture  Co. 

FIG.  I. — A  REGULAR  SHORE  AT  PROVINCETOWN,  MASSACHUSETTS,  SHOW- 
ING   LIFE-SAVING    CREW    RESCUING   A   MAN    FROM   A   WRECK. 

On  the  other  hand,  those  countries  that  have  a  much 
cut-up,  a  very  irregular  shore  line,  offer  unusual  oppor- 
tunities for  commerce  by  sea.  As  examples  of  such 
irregular  or  embayed  shore  lines,  study  the  eastern  coast 
of  the  United  States  from  New  York  northward,  the 
northern  shore  of  the  Mediterranean,  and  the  coast  of 
England,  and  note  how  they  are  lined  with  good  har- 
bors and  commercial  cities.  Of  course,  good  harbors  are 
not  all-important,  for  there  cannot  be  trade  and  com- 
merce unless  a  country  has  something  to  sell,  and  a 


THE   LAND.  13 

country  that  can  get  its  goods  to  market  with  the  least 
cost  and  delay  will  have  a  great  advantage  over  any  rival 
region.  This  suggests  another  reason  why  an  irregular 
shore  line  is  important,  for  the  bays,  running  far  into  the 
land,  give  vessels  a  chance  to  sail  nearer  to  the  heart  of 
the  country,  thus  allowing  goods  to  be  shipped  to  for- 
eign ports  or  to  other  coast  ports  without  long  journeys 
by  railroad  or  canal.  Hence  a  country  with  bays  and 
promontories  is  in  several  ways  better  fitted  for  trade 
than  a  country  whose  shore  line  is  formed  of  bold 
bluffs  or  stretches  of  sandy  beaches,  perhaps  miles  in 
length. 

The  coast  line  is  thus,  we  might  say,  the  key  to  the 
question  of  whether  a  country  will  be  powerful  and  rich 
or  not.  Of  two  countries  with  conditions  in  each  equally 
favorable  for  producing  riches,  and  with  equal  ability 
among  the  people  to  take  advantage  of  their  surround- 
ings, that  country  with  an  irregular  coast  ought  to  be  the 
more  prosperous.  • 

Back  of  the  coast,  however,  is  the  land,  and  it  is  only 
the  careful  study  of  the  land  that  will  tell  us  whether  the 
conditions  are  favorable  for  producing  the  commodities 
men  must  have  before  they  can  trade  for  those  things 
which  they  need  or  desire. 

The  Land. — Having  now  had  a  glimpse  of  the  larger 
features  of  the  continents  and'  oceans,  let  us  look  care- 
fully at  the  more  important  facts  in  reference  to  the  land, 
beginning,  perhaps,  with  our  own  continent.  To  get  a 
good  idea  of  such  an  extensive  area,  we  need  a  larger 
representation  than  the  small  patch  shown  on  a  globe. 
We  need  a  large  wall  map,  and  preferably  a  map  that 
shows,  among  other  things,  at  least  the  positions  o£  the 
principal  cities  and  towns,  the  larger  rivers,  the  bounda- 


14  A   READER  IN  PHYSICAL  GEOGRAPHY. 

ries  of  countries,  and  further,  one  that  indicates  roughly, 
by  different  shades  of  color,  the  height,  or  altitude,  of 
the  country  above  the  level  of  the  sea.  That  is,  we 
ought  to  be  able  from  the  map  to  tell  where  the  high- 
lands and  lowlands  of  a  country  lie. 

From  a  map  representing  so  large  an  area,  and  of  ordi- 
nary size,  we  can  gain,  of  course,  no  real  picture  of  the 
actual  aspect  of  a  country,  its  ups  and  downs,  its  slopes, 
its  valleys  and  streams;  but  we  can  learn  whether  the 
region  studied  should  be  called  mountainous  or  hilly;  and 
if  it  be  high  and  rugged,  we  can  see  how  broad  the  moun- 
tain mass  is,  and  in  what  direction  it  extends.  If  the 
region  be  low  and  flat,  we  know  it  to  be  a  plain ;  if  it  be 
high  and  more  or  less  level,  we  would  commonly  call  it 
a  plateau. 

Highlands  and  Lowlands. — Having  thus  located  the 
lowlands  and  highlands  of  a  region,  and  found  out  in  a 
rough  way  where  people  can  live  with  greatest  ease  and 
success,  we  are  ready  to  study  the  rivers  that  flow  from 
highlands  to  lowlands,  and  finding  out  whether  they  are 
large  or  small,  long  or  short,  swift  or  gentle,  we  shall  be 
able  to  tell  whether  they  give  means  of  commerce  or  fur- 
nish sufficient  water  for  factories  or  farms.  If  we  add 
to  these  facts  some  knowledge  of  the  climate,  we  have 
gained  a  good  idea  as  to  whether  the  country  as  a  whole 
is  habitable  or  not.  Highlands  with  few  rivers,  and  those 
inaccessible  because  of  steep  slopes,  we  would  naturally 
expect  to  be  forested,  to  be  the  home  of  wild  animals, 
and  perhaps  of  scattered  shepherds  and  herdsmen,  if 
men  could  live  there  at  all.  On  such  highland  masses 
we  would  expect  strong  and  probably  cold  winds,  with 
much  snow  in  the  winter,  and  a  short,  warm  summer. 
It  would  be  a  favorable  place,  if  conveniently  located, 


RELIEF  AND   ALTITUDE.  15 

for  summer  hotels,  but  in  most  ways  unfavorable  for 
man  the  year  round. 

We  would  expect  that  railways  and  carriage  ways 
across  the  mountain  ranges  would  be  few  and  far  apart, 
and  that  the  cost  of  building  and  keeping  good  roads  in 
repair  would  be  very  great.  It  would  be  difficult  for 
people  on  one  side  of  such  high  mountains  to  see  much 
of  their  neighbors  on  the  other  side.  The  Highlands  of 
Scotland,  for  instance,  have  many  deep,  narrow  valleys 
called  glens.  Those  who  live  in  the  same  glen  have 
grown  to  have  similar  customs,  and  to  be,  as  we  say, 
clannish,  distrustful,  and  perhaps  jealous  of  the  members 
of  other  clans. 

We  can  tell,  then,  from  such  a  map  study  the  direction 
and  character  of  the  streams  which  naturally  flow  from 
highlands  to  lowlands,  and,  in  a  general  way,  can  prophesy 
where  people  will  live,  what  they  will  do,  and  what  will 
be  their  relations  with  their  neighbors.  Such  prophesy- 
ing is  interesting,  as  the  working  out  of  a  puzzle  is  inter- 
esting, because  it  presents  problems  for  us  to  work  out, 
something  to  do  that  is  worth  doing,  and  that  is  agree- 
able. We  become  impatient  to  study  more  deeply 
and  to  find  out  how  far  our  conclusion  is  true,  and 
whether  we  have  made  any  mistake. 

Relief  and  Altitude. — Such  a  map  as  we  have  been 
considering  represents  the  general  relations  of  the  parts 
of  the  country  as  to  elevation  or  altitude,  or  shows  the 
relief,  as  we  may  say.  We  usually  speak  of  the  exact 
height  of  a  hill  or  a  mountain  as  its  altitude,  meaning 
thereby  the  exact  number  of  feet  that  the  top  of  the  ele- 
vation is  vertically  above  the  level  of  the  ocean.  It  is 
very  rare,  however,  that  a  person  can  stand  at  the  foot 
of  a  mountain  and  see  its  whole  height  in  one  glimpse. 


l6  A   READER  IN   PHYSICAL  GEOGRAPHY. 

Such  a  thing  is  impossible,  of  course,  unless  one  view  the 
mountain  from  the  seashore,  as,  for  instance,  in  Alaska, 
where  one  can  stand  on  the  shore  and  see  the  top  of  Mt. 
St.  Elias,  18,010  feet  high,  or  again  in  Japan,  where  from 
the  sea  one  can  look  to  the  top  of  Fuji-yama,  12,440  feet 
high.  Even  under  such  favorable  conditions,  however, 
we  cannot  really  appreciate  the  height  of  the  mountain, 
because  of  the  distance  of  the  peak,  and  for  other  reasons 


FIG.    2. — A    VIEW    OF    MOUNT    WASHINGTON    AND     NEIGHBORING     MOUN- 
TAINS, SHOWING    RELIEF    OF    REGION, 

that  make  it  difficult  to  judge  the  height  and  size  with 
accuracy. 

Usually  one  views  a  mountain  from  its  very  foot,  or 
from  a  very  short  distance  from  the  pedestal  on  which 
the  mountain  is  placed,  and  sees  only  a  certain  part  of 
the  whole  height  of  the  mountain,  as  in  the  White  Moun- 
tains' in  New  Hampshire,  where  one  stands  at  the  h  "-ight 
of  about  1,200  feet  as  he  views  the  summit  of  Mount 
Washington  rising  about  a  mile  above  him,  but  with  an 
altitude  of  6,291  feet.  (See  Fig.  2.)  Hence  we  need  to 
recognize  the  difference  between  exact  altitude,  which 


RELIEF  AND   ALTITUDE.  I/ 

can  rarely  be  seen,  and  visible  height.  The  visible  height 
of  a  point  above  the  adjacent  lowland  is  spoken  of  as  its 
relief,  and  a  country  with  many  sharp,  high  peaks  would 
be  said  to  have  a  strong  relief.  A  flat  and  monotonous 
country,  where  there  were  few  elevations  and  no  deep 
river  valleys,  would  be  of  slight  relief. 

It  is  the  relief  of  the  region  in  which  we  walk,  and  not 
its  altitude,  that  makes  us  weary;  for  it  is  not  the  being 
up,  but  the  going  up  and  down  that  takes  hold  of  our 
muscles.  In  very  high  mountains,  however,  where  the 
air  is  thin,  and  breathing  difficult,  the  effects  of  altitude 
are  important.  We  need  to  keep  in  mind  very  clearly 
this  difference  between  relief  and  altitude,  for  we  can  see 
and  test  relief  every  day,  whereas  we  can  but  rarely  test 
the  altitude  of  a  region.  Indeed,  the  hundreds  and 
thousands  of  people  in  the  United  States  who  have 
never  seen  the  ocean  have  not  had  a  chance  to  meas- 
ure by  their  eye  the  exact  altitude  of  any  feature  of  the 
earth's  surface. 

From  a  map  showing  the  relief,  then,  we  must  not 
expect  to  get  exact  ideas  of  a  region,  particularly  when 
a  map  represents  a  large  area  in  a  small  space.  We  can 
get  general  ideas  only,  but  yet  such  general  ideas  will 
allow  us  to  see  that  the  country  may  be  divided  roughly 
into  mountains  and  plains,  or,  as  we  may  perhaps  better 
say,  highlands  and  lowlands;  we  can  find  out  something 
of  the  general  height  of  the  lowlands,  so  that  we  may 
know  whether  to  call  them  plains  or  plateaus ;  we  can  get 
something  of  the  general  direction  of  the  mountains,  and 
see  the  difference  between  an  individual  peak,  like  a  vol- 
cano, and  a  series  of  peaks,  such  as  we  find  in  mountain 
ridges  or  ranges. 


CHAPTER    III. 

THE  LARGER  FEATURES  OF  THE  CONTINENTS—  Continued. 

Mountains. — Indeed,  we  should  notice,  as  we  study 
the  maps  of  the  various  continents,  that  single  mountains 
are  rare.  What  is  more  common  is  a  mass  of  highlands 
above  which  certain  peaks  rise  conspicuously.  These 
highest  peaks  are  often  points  of  interest  because  of  the 
view  to  be  obtained  from  them,  perhaps  at  the  expense 
of  much  hard  climbing,  accompanied  by  more  or  less 
danger.  (See  Fig.  3.)  The  mountain  peak,  however,  is 
not  the  barrier  that  the  traveller  finds  in  his  way  as  he 
attempts  to  cross  a  country,  for  he  can  avoid  the  peaks 
by  going  through  the  passes  or  gaps  between  them. 
(See  Fig.  69,  page  145.)  The  mountain  peaks  are  left  by 
themselves,  and  are  only  sought  out  by  the  professional 
tourist  (see  Fig.  4)  or  mountain  climber,  and  occasion- 
ally by  scientists  who  desire  the  pleasure  and  honor  of 
having  reached  the  top  of  some  extremely  high  and 
almost  inaccessible  peak,  or  the  credit  of  having  found 
some  particular  features  of  that  top  hitherto  unknown. 
The  mountain  mass  making  a  highland  is  the  great  bar- 
rier to  easy  travel,  and  thus  needs  our  first  and  our  most 
careful  attention. 

Continents  and  Highlands. — As  the  highlands  stand 
up  rigid  and  strong  as  compared  with  the  neighboring 
lands,  we  may  think  of  them  as  the  skeletons  of  the  con- 
tinents, giving  us  the  general  idea  of  the  whole  continent, 


CONTINENTS  AND   HIGHLANDS.  19 

just  as  the  skeleton  of  an  animal  gives  us  a  general  idea 
of  the  animal's  appearance  when  alive. 

Taking  our  own  continent   of    North  America  as   an 
example,  we  find  on  the  west  a  great  highland  known  as 


FIG.    3. — CLIMBING    A    HIGH     AND     STEEP-SLOPED    MOUNTAIN    IN    ENGLAND. 

the  Cordilleran  Highland,  commonly  divided  into  several 
systems  of  mountains.  From  the  western  slopes  of  these 
mountains  we  find  the  rivers  flowing  into  the  Pacific 
Ocean,  from  the  eastern  into  the  Gulf  of  Mexico,  or  in 
the  far  north  into  Hudson  Bay  or  into  the  Arctic  Ocean. 


20 


A   READER   IN   PHYSICAL   GEOGRAPHY. 


Between  these  river  systems  we  find  a  large  area  known 
as  the  Great  Basin,  in  which  the  water  accumulates  in 
depressions  that  have  no  outlet  to  the  sea,  of  which  Great 
Salt  Lake  in  Utah  is  an  excellent  example. 

We  find,  then,  that  the  Cordilleran  Highland  consists, 


FIG.    4. — AN    INCLINED    COG-WHEEL    RAILROAD    ON    PIKE  S    PEAK,     COLO- 
RADO,   USED    TO    CONVEY    TOURISTS    UP   THE    STEEP    SLOPES. 

throughout  part  of  its  extent  at  least,  of  an  eastern 
highland  and  a  western  highland,  with  an  elevated  area 
between,  with  what  we  call  internal  drainage.  Such 
an  arrangement  exists  in  other  continents,  and  may 
almost  be  said  to  be  an  essential  feature  of  the  highest 
and  broadest  highland  of  a  continent. 


LOWLANDS.  21 

On  the  east  of  North  America  we  have  the  Appala- 
chian Highland,  composed  of  several  series  of  mountain 
ranges,  and  from  which  many  large  rivers  flow  toward 
the  ocean  in  several  directions.  Much  of  the  water  goes 
to  the  west  into  the  Great  Central  Plain,  there  to  join  the 
waters  from  the  eastern  slopes  of  the  Cordilleran  High- 
land in  the  great  Mississippi  River.  Some  of  the  other 
rivers  of  the  Appalachians  flow  directly  to  the  Gulf  of 
Mexico,  or  to  the  Gulf  of  St.  Lawrence  by  way  of  the 
St.  Lawrence  River;  but  most  flow  directly  to  the  Atlantic 
Ocean  across  the  Atlantic  Plain  which  lies  to  the  east  of 
the  highlands.  North  of  the  St.  Lawrence  River  we  find 
a  faint  height  that  determines  whether  the  waters  of  the 
region  shall  go  to  the  St.  Lawrence  or  to  Hudson  Bay. 

The  important  physical  features  that  North  America 
has  in  common  with  other  continents  are  the  greater 
highland  (of  three  parts,  as  we  have  seen),  the  lesser  high- 
land, and  the  central  plain.  Considering  this  arrange- 
ment of  highlands  and  lowlands  as  the  skeleton  feature 
of  a  continent,  we  find  that  Eurasia  (Europe  and  Asia), 
North  America,  South  America,  Africa,  and  Australia 
may  be  called  continents.  Though  this  general  arrange- 
ment of  highlands  and  lowlands  is  found  in  each  conti- 
nent, it  should  be  noted  that  the  greater  highland  is  not 
always  on  the  western  side  of  the  continent,  as  is  espe- 
cially well  shown  in  Australia. 

Lowlands. — Turning  now  from  the  highlands,  which 
we  have  called  the  skeletons  of  the  continents,  let  us  look 
for  a  moment  at  the  lowlands,  which  may  be  likened  to 
the  flesh  between  the  bones  of  the  skeleton,  which  give 
life,  meaning,  and  form  to  the  continents  as  a  whole. 
We  have  already  seen  that  in  lowlands  the  relief  is  in 
general  not  strong,  and,  of  course,  the  altitude,  from  the 


22 


A   READER   IN   PHYSICAL   GEOGRAPHY. 


name,  is  relatively  low.  We  have  seen  that  highlands 
from  their  essential  character  are  unfavorable  to  human 
occupation,  except  for  scattered  herdsmen  or  lumbermen, 
or  possibly  miners,  and  that  the  whole  aspect  of  a  high- 
land is  forbidding  and  repellent  to  one  seeking  a  perma- 


FIG.  5. — A  LOWLAND  IN  CENTRAL  NEW  YORK  VIEWED  FROM  ADJOINING 
UPLAND.  NOTE  THE  POSITION  OF  THE  TOWN,  RAILROAD,  AND 
RIVER. 

nent  home  with  his  fellows.  In  contrast  we  find  the 
general  character  of  a  lowland,  other  conditions,  such  as 
climate,  being  favorable,  inviting  to  life,  and  especially 
to  human  occupation  and  activity..  (See  Fig.  5.)  The 
lowlands,  and  especially  the  great  lowlands  about  some 
of  the  great  rivers,  have  long  been  the  seat  of  the  most 
numerous  population  and  greatest  human  activity,  be- 


GREATER  NEW   YORK.  23 

cause  the  conditions  there  are  most  favorable  for  agri- 
culture, commerce,  travel,  and  all  the  necessary  industries 
of  life. 

When  we  come  to  consider  more  in  detail  the  features 
that  make  different  industries  possible,  we  shall  see  why 
lowlands,  more  than  highlands,  offer  the  requirements 
of  soil,  water,  slopes,  etc.,  which  enable  large  numbers  of 
people  to  congregate  and  find  the  means  of  living. 

It  is  not  enough,  however,  to  look  broadly  at  a  conti- 
nent as  a  whole,  as  we  see  it  on  a  map,  and  to  say  that 
here  men  would  live,  and  here  they  would  not;  such  an 
exercise  is  useful  as  giving  us  a  clue  to  those  parts  of 
the  continent  that  will  be  the  most  interesting  and  in- 
structive for  further  study.  But  such  a  single  glance 
cannot  prove  this  relation  of  highlands  and  lowlands  to 
life.  If,  however,  we  should  find  this  relation  in  several 
instances,  we  should  have  more  confidence  in  our  general 
view.  The  neighborhood  of  New  York  City  furnishes 
a  good  series  of  illustrations  of  these  conditions,  which 
we  may  take  as  an  example. 

Greater  New  York. — The  area  included  in  Greater 
New  York  maybe  divided  geographically  into  four  rather 
distinct  parts,  each  with  its  peculiar  features  of  topog- 
raphy, or  land  shapes,  and  its  own  peculiar  character  of 
living.  (See  Fig.  6.)  First  should  be  mentioned  the 
thickly  settled  area  of  the  Borough  of  Manhattan,  a 
somewhat  rolling  country,  mostly  concealed  by  flagstones 
and  houses,  interrupted  occasionally  by  masses  of  hard 
rocks  making  uplands  (we  can  hardly  call  them  highlands), 
seen  particularly  in  some  vacant  lots  and  in  such  preserved 
areas  as  Central  Park,  Mt.  Morris  Park,  Morningside  Park, 
etc.  The  conspicuous  elevations  of  Morningside  Heights 
and  Washington  Heights  are  the  regions  of  the  harder 


A  READER  IN   PHYSICAL   GEOGRAPHY. 


rocks   and    the   thinner   settlements.     The   rest   of   the 
borough  is  low  and  sandy,  and  was  once  the  seat  of  a 


Paterson 


Z,.^"$^l//^- 

I    -,,A  ^  ' 

.'•?:     --'^ss^^^^^- 

S  /  '.  .^U  1-'*         ,^  >^x~-rt  k'"*'1 


SCALE  OF  MILES 
12345 


FIG.    6. — MAP   OF   GREATER    NEW   YORK,    SHOWING    THE    SEVERAL  DIFFER- 
ENT    PARTS    OF   THE   REGION. 

number  of  small  streams  and  ponds,  long  since  super- 
seded by  sewer  pipes.  Similar  areas  of  irregular  upland 
and  lowland  compose  the  Borough  of  the  Bronx. 

The  lowlands  of  the  southern  portion  of  the  Island  of 


GREATER  NEW   YORK.  2$ 

Manhattan  and  of  the  flats  of  Harlem  have  always  been 
devoted  to  business  houses  or  to  residences.  As  the 
population  has  become  more  numerous,  some  of  the 
lower  uplands  have  been  occupied  by  homes  or  business 
blocks,  but  the  greater  heights  on  the  west  side  of  the 


FIG.    7. — A    "SQUATTER'S"    HOME   ON    A    ROCK,    MORNINGSIDE 

HEIGHTS,    NEW   YORK   CITY. 

city  have  in  part  been  made  into  parks  and  in  part  left 
unoccupied,  or  given  over  to  such  charitable,  religious, 
or  educational  institutions  as  Columbia  University,  St. 
Luke's  Hospital,  the  Protestant  Episcopal  Cathedral, 
etc.  Similarly  on  Washington  Heights,  the  extension 
of  the  same  ridge  north  of  i25th  Street,  we  find  many 


26  A   READER  IN  PHYSICAL  GEOGRAPHY. 

large  orphan  asylums,  homes  for  invalids,  the  site  of  the 
College  of  the  City  of  New  York,  etc. 

The  occasional  patches  of  good  land  among  the  rocks 
of  these  heights  have,  it  is  true,  been  occupied  by  small 
farmers,  but  the  population  has  not  been  numerous.  As 
the  herdsmen  of  Switzerland  build  their  summer  homes 
near  to  occasional  patches  of  good  ground  in  the  rocky 
heights,  so  the  so-called  "squatters"  in  Harlem  and 
other  parts  of  New  York  City  have  built  their  homes  on 
the  rocks  near  to  the  pasturage  for  their  cattle  and  goats, 
und  to  the  small  lots  capable  of  raising  a  few  vegetables 
and  flowers.  (See  Fig.  7.) 

As  the  two  boroughs  mentioned  are  somewhat  sim- 
ilar in  their  features,  so  are  the  Boroughs  of  Brooklyn, 
Queens,  and  Richmond.  (See  Fig.  6.)  In  each  of  these 
there  are  three  separate  divisions:  to  the  northward  and 
westward  an  irregular  rolling,  hilly  country,  abruptly  end- 
ing in  a  steep  slope  to  the  southeast  and  south,  that  faces 
a  plain.  The  plain  continues  to  the  ocean,  and  is  fringed 
by  a  series  of  recently  formed  beaches  and  bays.  Within 
these  boroughs,  again,  we  find  the  same  occupation  of 
lowlands,  and  a  general  avoidance  of  uplands.  The  low 
plains  of  Long  Island  and  Staten  Island  are  mostly  cov- 
ered with  large  truck  farms,  from  which  comes  a  large 
share  of  the  vegetables  for  the  city  markets.  The 
heights  of  Staten  Island,  Brooklyn,  and  Jamaica  are 
more  used  for  residences  or  for  parks,  as  in  the  Borough 
of  Manhattan. 

Summary. — We  have  seen  that  the  world  consists  of 
air,  water,  and  earth ;  that  the  earth  underlies  the  water 
and  air,  and  that  the  continents  are  but  the  higher  parts 
of  the  rock  earth  not  covered  by  the  water;  that  the 
line  where  the  earth  and  water  meet  is  called  the  shore 


SUMMARY.  27 

line  or  coast  line,  and  that  the  shape  may  be  of  great 
importance.  Further,  looking  at  the  land,  we  have  found 
that  the  continents,  the  home  of  man,  are  composed  of 
lowlands  and  highlands,  and  that  on  the  form  and  arrange- 
ment of  each  depend  many  things  in  reference  to  man's 
life;  and,  finally,  that  in  a  general  way  we  should  expect 
man  to  be  more  numerous  in  the  lowlands  and  more  scat- 
tered in  the  highlands,  as  we  have  seen  illustrated  about 
New  York  City.  Let  us  next  see  what  men  can  do  to 
make  a  living  amid  such  different  conditions,  and,  if  pos- 
sible, some  of  the  reasons  for  their  mode  of  life. 


THE    INDUSTRIES    OF    MEN. 

CHAPTER   IV. 

CENTRES   OF    INDUSTRY. 

Importance  of  Work. — There  is  a  well-known  saying, 
"  Man  cannot  live  without  work,"  and  certainly  it  is  true 
that,  the  world  over,  men  must  labor  to  get  the  necessary 
food  and  clothing  from  the  earth,  or  from  the  animals 
and  plants  of  the  earth.  The  savage,  living  amidst  the 
luxuriant  vegetation  and  the  numerous  animals  of  the 
tropical  forests,  would  seem  at  first  sight  not  to  have  to 
work  for  a  living.  But  the  animals  must  be  ensnared  and 
killed,  and  the  fruits  and  roots  must  be  gathered,  and 
perhaps  dried  and  cooked,  before  the  savage  can  enjoy 
the  riches  about  him.  The  labor,  perhaps,  is  small,  and 
the  return  large;  but  it  is  often  more  difficult  than  it 
would  seem  at  first,  and  however  much  the  savage  may 
seem  to  us  a  lazy,  indolent  creature,  there  are  times  when 
he,  like  his  neighbor  the  large  reptile,  must  wake  up  to 
the  demands  of  hunger,  and  work  for  his  food. 

If  we  pass  from  the  tropics  to  the  far-distant  polar 
lands,  we  find  labor  even  more  necessary  in  order  that 
the  native  may  live.  The  Eskimo,  living  where  he  can- 
not till  the  land,  must  depend  for  food  upon  the  animals 
and  fish  that  he  can  catch.  He  must,  by  patient  and 
hard  work,  secure  his  food  and  most  of  the  necessities  of 


IMPORTANCE  OF  WORK.  29 

life  from  the  sea.  Hard  work  is  his  daily  experience. 
His  main  industries  are  hunting  and  fishing. 

If  we  look  about  us  in  the  temperate  lands  in  which 
the  white  man  mostly  makes  his  home,  we  find  that  the 
simpler  industries  of  hunting  and  fishing  (except  sea  fish- 
ing), by  which  man  wrests  his  food  first-hand  from  nature, 
are  largely  confined  to  the  wild  parts  of  the  world  into 
which  man  is  just  penetrating.  In  the  forests  and  waters 
of  the  uninhabited  frontier  of  the  country  we  find  hunt- 
ing and  fishing  for  food  and  furs ;  but  in  the  more  thickly 
settled  countries  people  live  mostly  by  other  industries, 
many  of  which  demand  that  they  shall  dwell  thickly  to- 
gether to  secure  a  good  result  from  their  labors.  Again, 
we  find  that  the  individual  person  is  not  himself  securing 
all  he  needs  in  life  by  his  own  direct  labor,  but  that  he  is 
devoting  himself  to  doing  some  one  thing  well,  with  the 
expectation  of  trading  the  result  of  his  work  for  the  other 
things  that  his  neighbors  are  producing — things  that  he 
must  have  in  order  to  live. 

If  we  go  to  the  mountains  of  Tennessee  and  Kentucky, 
we  shall  find  the  people  in  general  living  in  scattered, 
small  settlements,  perhaps  but  one  house  to  a  place.  Not 
infrequently  we  shall  find  each  family  raising  its  own  vege- 
tables, and  perhaps  tobacco,  for  use  during  the  whole 
year,  raising  its  own  hogs  and  chickens  to  furnish  meat, 
weaving  and  spinning  its  own  clothes,  and  making  its 
own  flour  from  the  products  of  the  fields.  Here  trade 
and  commerce  are  almost  unknown,  for  there  are  few 
commodities  raised  in  sufficient  abundance  to  sell,  and 
few  people  to  buy,  even  if  there  were  anything  to  sell. 
What  trade  there  is,  is  largely  confined  to  the  exchange 
of  products  at  the  country  store  for  certain  goods  that 
cannot  be  raised.  This  form  of  direct  swapping  without 


30  A   READER  IN   PHYSICAL  GEOGRAPHY. 

the  use  of  money  is  known  as  barter.  Such  a  method  of 
living  is  not  profitable  or  easy,  for  it  does  not  allow  peo- 
ple to  have  many  things  other  than  those  that  are  abso- 
lutely necessary. 

Centres  of  Life. — People  have  by  experience  found 
it  pleasanter  and  of  greater  advantage  to  live  in  more 
or  less  thickly  settled  communities  or  centres,  and  there 
to  carry  on  many  different  industries,  each  man  doing 
one  task  and  doing  it  well.  In  the  early  history  of 
this  country,  however,  people  came  to  live  together 
not  only  for  such  mutual  help,  but  because  they  could 
thus  better  protect  themselves  against  the  Indians  and 
wild  animals.  As  a  result  we  have  villages,  towns,  or 
cities,  varying  in  size  from  a  population  of  a  dozen  to 
that  of  millions.  The  towns  and  villages  have  increased 
in  size  and -number  very  rapidly  in  the  last  fifty  years, 
until  we  have  come  to  think  that  the  prosperity  of  a 
region  is  shown  by  the  number  of  large  cities. 

In  each  centre  of  life  we  usually  find  some  one  con- 
spicuous industry  that  forms  the  trade  or  occupation  of 
the  majority  of  the  people,  or  there  is  some  one  good  rea- 
son that  has  caused  people  to  gather  there  in  numbers. 
We  describe  the  centre  by  its  principal  industry,  and  from 
this  it  gets  its  reputation.  For  instance,  we  speak  of  New 
York,  or  Chicago,  or  Liverpool,  or  Calcutta,  or  Rio  Janeiro, 
as  great  commercial  centres,  meaning  that  there  people 
trade,  gathering  products  from  the  country  about  them 
to  send  to  other  countries,  and  bringing  in  return  the 
commodities  from  abroad  that  are  needed  at  home.  We 
speak  of  Lowell,  Massachusetts;  Paterson,  New  Jersey; 
Manchester,  England,  and  other  similar  cities  as  manu- 
facturing centres,  meaning  that  there  people,  by  means 
of  machinery  and  their  own  hands,  turn  the  cotton,  or 


CENTRES   OF   LIFE.  31 

iron,  or  other  so-called  raw  product  into  the  finished 
utensil  or  article  of  clothing,  etc.  Thus  there  must  be 
centres  of  different  kinds  in  the  different  parts  of  the 
same  country,  so  that  by  trade  each  person  may  secure 
most  of  his  needs  without  difficulty. 

If  we  attempt  to  enumerate  the  various  kinds  of  cen- 
tres, we  shall  find  the  following  to  be  the  most  important 
groups  : 

Commercial  centres,  where  trading  is  carried  on  on  a 
large  scale;  agricultural  centres,  about  which  are  large 
farms  or  plantations  from  which  come  the  grains,  vege- 
tables, and  fruits  that  are  used  for  food,  or  the  cotton 
that  is  made  into  clothing;  grazing  centres,  about  which 
cattle,  sheep,  hogs,  or  horses  are  raised  in  large  numbers 
for  food,  or  for  other  uses  (grazing  centres  would  include 
the  dairying  centres  from  which  come  our  milk,  butter, 
and  cheese) ;  lumbering  centres,  at  which  timber  is  cut 
to  supply  lumber  for  houses,  factories,  stores,  furniture, 
ships,  to  make  wood  pulp  for  paper,  etc. ;  manufacturing 
centres,  at  which  raw  products  are  made  into  needed  arti- 
cles for  home  use  and  commerce ;  mining  centres,  at  which 
valuable  minerals,  ores,  or  rocks  are  taken  from  the  earth; 
fishing  centres,  from  which  men  go  to  catch  the  fish  of 
.rivers,  lakes,  or  ocean  ;  and,  finally,  a  group  of  centres  that 
may,  for  lack  of  a  better  name,  be  called  scenic  centres, 
to  which  visitors  are  attracted  by  beautiful  scenery,  good 
air,  a  chance  for  rest,  or  by  some  object  of  historical  in- 
terest. Some  centres,  producing  products  that  are  abso- 
lutely necessary,  are,  of  course,  much  more  important 
than  other  centres.  As  we  must  eat,  and  have  wool  or 
cotton  for  clothing,  agricultural  and  grazing  centres  may 
be  said  to  be  the  most  essential  to  each  one  of  us.  Simi- 
larly, there  must  be  manufacturing  centres,  where  cloth- 


32  A   READER  IN   PHYSICAL  GEOGRAPHY. 

ing  is  made  from  the  raw  cotton  or  wool,  and  where  other 
needful  articles  are  produced. 

One  part  of  a  country  is  best  fitted  to  be  one  form 
of  centre,  and  another  another,  inasmuch  as  success  in 
any  of  these  forms  of  industry  demands  a  special  series 
of  conditions  differing  from  the  conditions  in  any  other 
centre.  Although  there  are  many  forms  of  industry  often 
carried  on  together  in  any  large  city,  the  city  gets  its 
reputation  from  that  kind  of  work  for  which  the  con- 
ditions are  by  nature  the  most  favorable,  as  is  well  illus- 
trated in  New  York  City,  where  every  sort  of  industry  is 
carried  on,  but  where  commerce  is  the  most  important. 

If  we  know  the  conditions  that  make  any  particular 
industry  possible  or  profitable,  we  shall  be  able  to  under- 
stand the  more  important  reasons  for  the  growth  of  some 
of  the  larger  cities  of  the  world,  and  the  distribution  of 
industries  in  our  country  and  others.  From  such  a  study 
we  shall  get  a  better  idea  of  the  geographic  conditions  of 
the  inhabited  part  of  the  world,  for  we  shall  study  the 
world  not  as  so  much  land  and  water,  but  as  the  home 
of  the  many  varied  forms  of  life. 


CHAPTER  V. 

CENTRES   OF    INDUSTRY—  Continued. 

Commercial  Centres. — In  order  to  be  a  good  centre 
for  trade,  a  town  must  be  so  situated  that  it  can  secure 
a  large  amount  of  goods  to  be  sold  with  the  least  cost  for 
carriage  from  the  farm,  factory,  forest,  or  mine.  It  must 
have,  also,  a  feady  means  for  sending  the  goods  away  to 
other  cities,  or  other  countries,  at  small  cost  and  with 
little  delay.  Chicago,  Illinois,  for  example,  is  so  placed 
at  the  southern  end  of  Lake  Michigan  that  it  is  the  very 
centre  of  the  great  farming  country  of  the  prairies,  and 
naturally  draws  to  itself  the  products  of  the  region  round 
about,  especially  grain  and  beef.  It  also  has  easy  rail- 
road connection  with  all  its  neighboring  cities,  and  by 
several  direct  routes  with  the  great  seaports  of  the  At- 
lantic coast,  particularly  New  York  and  Boston.  No 
less  important  is  its  ready  water  connection  with  the 
Atlantic,  by  means  of  the  Great  Lakes,  the  several 
canals,  and  the  St.  Lawrence  River.  By  its  position  at 
the  centre  of  a  large  area  from  which  it  can  draw  goods 
by  railroad,  it  is  like  a  garden  spider  which  has  a  great 
web  spread  over  the  grass,  from  any  part  of  which  it  can 
gather  prey.  Once  gathered,  the  spider  withdraws  into 
its  round,  tunnel-like  hole,  and  gets  rid  of  its  spoil. 
From  wherever  gathered,  the  prey  disappears  by  one 
route.  In  a  similar  way  we  find  that  the  larger  part  of 
the  goods  gathered  to  Chicago  are  sent  eastward,  along 
the  routes  mentioned,  to  the  great  seaports. 
3 


34  A   READER   IN  PHYSICAL   GEOGRAPHY. 

New  York  City  is  another  example  of  a  great  seaport 
and  commercial  centre.  Here  the  wonderful  ease  of 
communication  with  Chicago  and  the  other  large  cities 
of  the  great  West,  by  means  of  the  Hudson  River  Valley 
and  the  Mohawk  Valley,  insures  a  large  supply  of  prod- 
ucts for  exportation.  The  deep,  large,  and  protected 
harbor,  the  nearest  of  the  better  Atlantic  harbors  to  the 
great  ports  of  Europe,  gives  ready  access  to  the  largest 
vessels  of  all  the  commercial  nations  of  Europe  and 
South  America.  Again,  the  protected  pathway  of  Long 
Island  Sound  gives  an  excellent  opportunity  for  coast- 
wise trade  with  the  New  England  States  aftd  the  eastern 
provinces  of  Canada.  For  these  reasons,  and  also  because 
of  its  ease  of  communication  with  the  West  and  South- 
west, New  York  has  naturally  become  a  commercial 
centre,  and  the  greatest  in  the  United  States.  Other 
examples  might  be  given,  but  these  two  give  us  all  the 
facts  necessary  to  account  for  the  growth  of  a  commercial 
centre. 

All  commercial  centres  are  not,  however,  large  cities; 
for  any  city  so  situated  as  to  accommodate  the  country 
or  region  round  about  it  will  probably  be  a  commercial 
centre.  The  farmer  who  sells  his  vegetables  in  a  neigh- 
boring town  and  procures  groceries  there  to  take  to  his 
home  is  helping  make  that  town  a  commercial  town,  in 
the  same  way  that  a  large  importing  and  exporting  house 
in  New  York  City  helps  make  that  a  commercial  centre. 
Something  to  sell  or  exchange,  a  cheap  and  quick  way  to 
carry  it,  and  somebody  with  energy  enough  to  set  the 
trade  in  motion  are  the  requirements  of  a  commercial 
centre,  large  or  small. 

But  the  process  of  exchanging  one  form  of  goods  for 
another  on  a  large  scale  is  not  so  simple  as  it  would  seem 


COMMERCIAL  CENTRES.  35 

at  first.  A  large  commercial  city,  like  those  mentioned, 
must  have  many  large  wholesale  houses,  perhaps  each 
devoted  to  one  thing,  like  leather,  cotton  goods,  woollen 
goods,  sugar,  etc.  At  such  a  wholesale  house  no  one  can 
buy  a  small  quantity  of  goods,  and  no  local  customers  are 
supplied,  unless  it  be  the  large  retail  stores  that  buy 
goods  in  large  quantities.  Each  such  house  or  firm  must 
also  have  a  large  storehouse,  where  the  goods  can  be 
kept  after  they  are  received,  and  from  which  they  can 
be  readily  shipped.  Large  commercial  and,  indeed,  all 
large  business  centres  must  also  have  banks,  to  accom- 
modate the  irfen  who  do  not  pay  for  goods  directly  by 
money,  but  by  checks  or  drafts  on  their  store  of  money 
deposited  in  the  bank.  Insurance  companies  are  neces- 
sary, to  insure  the  goods  that  are  kept  in  stock  by  the 
large  firms.  There  must  be  also  large  railway  freight 
yards,  where  many  thousands  of  freight  cars  can  be 
loaded  or  unloaded  at  one  time.  Chicago,  for  instance, 
is  noted  as  being  the  largest  railway  centre  in  the  world. 
If  a  city  is  engaged  in  water  commerce,  there  must  be 
wharves  and  docks  that  allow  vessels  to  land  and  dis- 
charge their  cargoes  easily.  It  is  the  presence  of  such 
wharves  on  both  sides  of  the  lower  Hudson  River,  along 
the  so-called  "water  fronts"  of  New  York  and  the 
neighboring  cities  in  New  Jersey,  that  makes  their  water 
trade  possible. 

As  such  extensive  business  demands  the  activities  of 
many  people,  a  trade  centre  may  grow  into  a  large  city, 
with  its  thousands  of  homes,  as  we  find  in  New  York, 
Chicago,  Philadelphia,  etc.  Large  numbers  of  people 
demand  quantities  of  supplies,  to  give  them  food  and 
clothing,  and  hence  great  numbers  of  stores  of  all  kinds, 
many  places  of  amusement,  quick  means  of  getting  from 


A  READER  IN  PHYSICAL   GEOGRAPHY. 


one  part 
activities 
Most  of 
business 
gregated 
the  city 


of  the  area  to  another,  and  all  the  other  human 
and  devices  that  go  to  make  up  a  large  city. 

these  conditions  exist  in  a  similar  way  in  any 

centre  where  large  numbers  of  people  are  con- 
together,  and  by  their  presence  help  to  make 

larger  and   more   complete.     A  manufacturing 


FIG.    8. — A    CULTIVATED  AREA    IN    IRELAND.       NOTE   THE   DISTRIBUTION    OF 
THE    TILLED    FIELDS   ON   THE    MORE    GENTLE    SLOPES. 

city  has  thus  many  things  in  common  with  a  commercial 
city. 

Agricultural  Centres. — The  most  important  thing  in 
determining  the  success  of  agriculture  is  land  with  slopes 
that  can  be  cultivated.  (See  Fig.  8.)  If  the  slopes  are 
too  steep,  the  water  of  the  soil  will  run  away  too  rapidly, 
and  tilling  will  be  difficult,  if  not  impossible.  In  such 
an  area  the  soil  will  wash  away  after  a  rain,  so  that  there 


AGRICULTURAL   CENTRES. 


37 


can  be  no  surety  about  a  crop  once  planted  staying  in 
the  ground  undisturbed  until  the  harvest.  Next  to  the 
need  of  a  slope  not  too  steep  to  hold  the  soil  is,  of 
course,  the  need  of  good  soil.  There  are  many  things 
that  determine  whether  a  soil  is  good  or  bad,  but  the 
principal  thing  is  that  it  contain  the  materials  that  the 
plants  require  for  food.  The  soils  that  are  found  in  the 


By  permission  of  Detroit  Photographic  Co. 

FIG.    9. — A    COTTON    FIELD    IN    THE    RICH    LOWLAND    OF   THE    MISSISSIPPI 

RIVER. 

lower  slopes  of  rivers  are  the  best,  because -they  are  very 
fine  and  composed  of  many  different  kinds  of  material. 
Hence  such  river  lowlands,  as  we  have  already  seen, 
furnish  the  best  farm  lands,  if  other  conditions  favor 
their  use.  (See  Fig.  9.)  Next  to  the  two  needs  already 
mentioned  is  a  good  climate — that  is,  there  must  be 
plenty  of  rain,  but  not  too  much;  there  must  be  plenty 
of  warmth,  and  a  sufficiently  long  summer  for  the  crops 
to  ripen.  Finally,  the  region  must  be  in  easy  communi- 


38  A   READER   IN   PHYSICAL   GEOGRAPHY. 

cation  with  a  large  commercial  centre  at  which  the  prod- 
ucts of  the  farm  can  be  sold  for  money,  or  for  goods 
that  the  farmer  needs.  If  the  farmer  wishes  to  raise  fruit 
or  vegetables,  or  some  other  thing  that  must  be  used  as 


FIG.     10. — AN     IRRIGATED     FIELD     IN     SOUTH    DAKOTA.        NOTE    ARRANGE* 
MENT    OF    DITCHES    BY    WHICH    WATER    IS    FED    TO    CROPS. 

soon  after  gathering  as  possible,  then  it  is,  of  course,  a 
great  advantage  to  be  as  near  as  possible  to  a  large  city. 
In  the  vicinity  of  New  York  City  there  are  wonderful 
illustrations  of  this  kind  of  farming  in  the  low  flat  plains 
of  southern  Long  Island  or  Staten  Island,  and  in  the 
many  farms  in  the  valley  of  the  Passaic  River  in  New 
Jersey,  but  a  few  miles  from  several  large  cities.  Here 


AGRICULTURAL  CENTRES.  39 

we  have  all  the  necessary  features  for  successful  market 
gardening,  as  it  is  called:  a  low  plain  with  good  soil, 
plenty  of  water,  and  a  good  climate,  within  easy  reach  of 
a  large  city  that  will  make  use  of  the  products  as  fast  as 
they  are  ready  for  market.  In  the  isolated  little  fields, 
now  rapidly  giving  way  to  apartment  houses,  in  the  north- 
ern end  of  New  York  City  we  have  just  as  good  illustra- 
tions of  farms,  but  on  a  much  smaller  scale. 

If  we  go  to  the  Southern  States  and  study  the  cotton, 
rice,  or  sugar-cane  plantations,  or  to  the  Western  grain 
fields,  we  find  the  same  need  of  slope,  soil,  and  climate 
favorable  for  inexpensive  tillage.  Here,  however,  there 
is  no  need  of  a  neighboring  market,  as  these  crops  are 
capable  of  being  transported  to  great  distances  without 
loss  of  value. 

In  the  large  plantations  of  the  South  or  West,  in  the 
large  farms  of  Pennsylvania  or  New  York,  or  in  the  small 
farms  of  New  England,  we  find  the  same  need  for  the 
favoring  conditions  we  have  named.  So  that  we  may 
regard  these  as  the  important  conditions  for  farming, 
seemingly  of  importance  in  the  order  named.  This  does 
not  mean  that  agriculture  cannot  be  carried  on  where 
these  conditions,  or  some  of  them,  are  absent;  for  where 
there  is  too  little  rain,  irrigation  or  artificial  watering  of 
the  soil  gives  the  needed  moisture.  (See  Fig.  10.)  In 
the  cold  weather  of  the  New  York  winter,  crops  are 
grown  under  glass  in  small  hot-houses,  thus  securing 
large  profit  at  a  considerable  expense  of  labor  and 
money. 

To  be  profitable,  however,  farming  demands  the  con- 
ditions mentioned  ;  and  the  Mohawk  Valley  of  New  York 
State  with  its  many  large  hay  and  vegetable  farms, 
South  Carolina  with  its  rice  swamps,  Mississippi  and 


40  A   READER   IN   PHYSICAL  GEOGRAPHY. 

Alabama  with  their  cotton  plantations,  Illinois  and  Ohio 
with  their  great  prairie  farms,  and  the  Dakotas  with 
their  wheat  fields  are  some  of  the  regions  of  the  United 
States  that  are  the  best  adapted  naturally  for  agriculture, 
and  they  are  renowned  the  world  over  as  among  the  best 
agricultural  centres. 


FIG.  II. — A  LARGE  DAIRY  FARM  IN  NEW  YORK  STATE,  SHOWING  LARGE 
CATTLE  BARN,  TILLED  GENTLE  SLOPES,  AND  STEEPER  SLOPES  DE- 
VOTED TO  GRAZING. 

Grazing  Centres. — The  conditions  that  make  grazing 
the  principal  occupation  of  a  region  vary  but  little  from 
those  necessary  for  agriculture.  There  is  the  same  need 
for  soil  that  will  raise  food  for  cattle  and  other  animals, 
though  the  soil  need  not  be  of  the  best.  On  the  larger 
dairy  farms,  however,  there  must  be  good  soil  and  rich 
pastures  from  which  the  cattle  may  get  the  best  of  food 


GRAZING   CENTRES.  4! 

if  the  industry  is  to  be  profitable.  (See  Fig.  n.)  On 
the  large  cattle  ranches  of  the  Southwest  and  West  the 
amount  of  food  on  a  given  area  is  very  small,  and  thus 
the  cattle  wander  far  and  wide  to  seek  the  necessary 
grass.  (See  Fig.  12.)  Next  to  the  need  of  a  soil  not 
too  barren  to  raise  food  is  the  need  of  sufficient  rainfall 
in  the  growing  season,  to  furnish  the  soil  all  the  water 


FIG.  12. — A  GRAZING  RANGE  IN  ARID  NEW  MEXICO.  IN  THE  CENTRE 
OF  THE  PICTURE  IS  SEEN  ONE  OF  THE  INTERMITTENT  STREAMS 
OF  THE  REGION. 

needed.  We  find,  too,  that  the  slopes  over  which  cattle 
may  wander  in  search  of  food  do  not  need  to  be  as  gentle 
or  smooth  as  those  devoted  to  agriculture.  The  country 
can  also  be  more  irregular  in  shape  or  topography,  more 
cut  up  and  more  interrupted  by  ledges  of  hard  rock  than 
it  should  be  in  an  agricultural  region.  (See  Fig.  13.) 

We  thus  see  that  the  conditions  for  grazing  are  but 
varieties  of  the  conditions  for  agriculture.     Indeed,  if  we 


42  A   READER   IN   PHYSICAL  GEOGRAPHY. 

go  to  a  New  England  or  a  New  York  farm,  we  shall 
usually  find  a  certain  part  of  the  farm  devoted  to  pastur- 
ing cattle,  horses,  sheep,  or  hogs.  The  lower  lands  and 
the  smoother,  more  gentle  slopes  are  devoted  to  the  vari- 


FIG.   13. — A,,  ROLLING   VERMONT   FARM,  WITH   ALL  BUT   LOWER    SLOPES 
DEVOTED   TO    GRAZING   AND    FORESTS. 

ous  crops,  to  hay  or  grain  fields.  As  we  climb  the  hills 
and  the  slopes  grow  more  steep,  or  as  we  descend  into 
the  areas  too  wet  for  ploughing,  we  find  the  pasture 
lands,  and  perhaps  at  the  top  of  the  hills  we  may  come 
into  the  woods  in  which  the  cattle  may  have  a  chance  to 


LUMBERING  CENTRES.  43 

feed.  In  some  parts  of  the  country,  as,  for  instance,  in 
Arizona  and  New  Mexico,  cattle,  sheep,  and  goats  will 
be  found  in  the  forests  to  the  summits  of  mountains  that 
are  more  than  a  mile  and  a  half  in  height. 

The  other  condition  noted  as  important  in  determining 
the  success  of  farming  is  nearness  to  a  good  market. 
This  would  seem  also  to  be  an  important  element  in  graz- 
ing, and  it  is  in  some  cases.  But  if  the  grazing  consists 
in  the  raising  of  cattle,  horses,  sheep,  or  hogs  for  the 
market,  then  nearness  to  a  large  city  is  not  so  important, 
as  the  cattle  can  be  shipped  alive  long  distances  at  small 
cost,  and  be  slaughtered  at  large  establishments,  such  as 
the  great  slaughter-houses  of  Chicago  or  Kansas  City. 
Again,  if  a  region  is  devoted  to  the  production  of  but- 
ter and  cheese,  which  can  be  kept  for  a  long  time  before 
being  used,  then  an  accessible  market  is  not  important. 
If,  on  the  other  hand,  the  dairyman  wishes  to  produce 
milk  and  cream  for  market,  nearness  to  a  large  city  is 
very  important,  for  such  products  cannot  be  shipped  very 
far  without  great  expense  and  the  danger  of  spoiling. 
We  thus  find  milk  for  people  living  in  New  York  City 
coming,  for  instance,  from  as  far  distant  as  Delaware 
County,  New  York,  or  Pittsfield,  Massachusetts.  About 
this  latter  place,  and  in  the  Berkshire  Hills  to  the  south, 
are  all  the  necessary  conditions  for  profitable  grazing, 
accompanied  by  more  or  less  profitable  farming.  Here 
on  the  uplands,  bordering  the  Housatonic  River  and  its 
branches,  are  good  water,  fair  soil,  rugged,  rough  land, 
often  with  steep  slopes,  all  within  a  few  hours  of  a  large 
market.  Dairy  farming  is  consequently  important  and 
successful  in  this  region. 

Lumbering  Centres. — In  certain  parts  of  the  world,  as 
in  the  Adirondacks  in  New  York  State,  nearly  all  the 


44 


A   READER  IN   PHYSICAL  GEOGRAPHY. 


land  is  covered  by  forests.  In  some  cases  the  forests 
are,  as  we  say,  "primeval" — that  is,  they  have  never 
been  used  by  man  except  as  a  pleasure  or  hunting 
ground ;  in  other  cases  the  trees  are  rapidly  being  cut 
from  extensive  areas  for  use  in  various  ways.  The  early 
settlers  on  the  Atlantic  coast,  especially  in  New  England 
and  about  New  York  City,  had  to  remove  the  forests 

before  they 
could  attempt 
any  farming,  or 
even  get  a 
clearing  large 
enough  so  that 
their  home  in 
the  centre 
would  not  be 
open  to  attack 
from  Indians 
in  the  forest. 
In  the  moun- 
tain forests  of 
Tennessee, 
Georgia,  and 
Alabama  one 

frequently  finds  a  school-house  in  a  clearing  in  the  woods. 
The  school-house  has  been  located  so  as  to  be  accessible 
to  many  families  and  may  be  out  of  sight  of  any  house, 
(See  Fig.  14.) 

As  the  population  has  increased,  the  forests  have  been 
removed  to  make  room  for  farms  and  towns,  until  now 
there  are  no  extensive  forests  in  the  United  States  ex- 
cept in  somewhat  inaccessible  regions,  or  on  lands  that 
cannot  be  devoted  to  farming  or  grazing.  Where  small 


FIG.  14. — A  LOG  SCHOOL-HOUSE  IN  A  FOREST 
CLEARING  IN  ALABAMA.  THIS  HOUSE  IS  ALSO 
USED  AS  A  CHURCH. 


LUMBERING  CENTRES. 


45 


patches  of  forest  occur  on  farms,  they  usually  are  found 
where  the  slopes  are  most  steep,  the  soil  the  poorest, 
and  perhaps  the  visible  rocks  the  most  numerous. 

Thus  we  may  sum  the  matter  up  by  saying  that  where 
soil,  slope,  and  inaccessibility  to  market  all  unite  to  ren- 
der other  ways  of  getting  a  return  from  the  soil  impossi- 
ble, we  may  expect  to  find  forests. 


FIG.  15. — A  TEMPORARY  LUMBER  MILL  AND  CAMP  IN  WASHINGTON. 

In  those  regions  where  the  forests  are  now  being  cut 
for  lumber  or  for  wood  pulp  which  is  made  into  paper, 
men  are  gathered  together,  often  in  large  numbers,  in 
what  may  be  called  lumbering  centres.  In  some  cases, 
however,  especially  in  parts  of  the  northern  United 
States,  lumbering  is  carried  on  only  in  the  winter,  when 
the  ground  is  covered  with  snow,  and  the  rivers  and 
swamps  frozen  so  that  men  and  teams  can  go  easily  in 


46  A  READER  IN  PHYSICAL  GEOGRAPHY. 

any  direction.  Lumbering  camps  thus  may  be  centres 
of  periodic  activity,  and,  like  some  other  centres,  practi- 
cally deserted  at  certain  seasons.  (See  Fig.  15.)  Lum- 
bering towns,  where  lumber  is  sawed  and  prepared  for 
market,  and  from  which  it  is  shipped,  are,  on  the  other 
hand,  centres  of  continual  life.  In  each  case  the  peculiar 
geographical  conditions  that  have  made  lumbering  prof- 
itable and  possible  are  the  cause  of  the  gathering  of 
people  in  numbers. 


CHAPTER   VI. 

CENTRES    OF    INDUSTRY.— Continued. 

Manufacturing  Centres. — Manufacturing  centres,  at 
which  raw  products  of  the  earth  are  changed  into  the  fin- 
ished goods  of  commerce  and  trade  through  the  agency 
of  machinery,  and  of  the  men  and  women  who  manage 
the  machines,  are  now  among  the  most  important  places 
in  the  world.  When  one  speaks  of  manufacturing,  the 
first  suggestion  that  comes  to  his  mind  is  power,  some 
force  of  nature  that  man  can  turn  to  his  own  use  to  aid 
him  to  work  more  rapidly  and  to  better  advantage  than 
by  his  own  hands.  The  power  that  may  be  employed 
varies  in  different  places.  In  some  places  dogs  and 
horses,  or  perhaps  even  men,  by  means  of  a  treadmill, 
produce  power  of  great  value.  For  instance,  on  some 
farms  horses  furnish  power  for  sawing  wood,  cutting  up 
corn-stalks  for  cattle,  and  dogs  may  churn  the  butter. 
Our  usual  idea  of  the  power  for  manufacturing,  however, 
is  either  steam  or  water  power.  (See  Fig.  16.)  In  the 
early  settlement  of  this  country  there  were  many  towns 
founded  near  waterfalls  that  gave  power.  Some  of  these 
towns  survived,  and  because  of  the  water  power,  later 
aided  by  the  possible  steam  power,  have  become  great 
manufacturing  centres.  The  name  of  the  town  often 
suggests  to  us  the  water  power  which  primarily  was  the 
cause  of  its  growth,  as  in  the  case  of  Fall  River  and 
Turners  Falls,  Massachusetts  ;  Glens  Falls  and  Little 
Falls,  New  York  ;  and  Bellows  Falls,  Vermont, 


48  A  READER  IN   PHYSICAL  GEOGRAPHY. 

A  good-sized  waterfall  is  a  source  of  great  power  (see 
Fig/  1 6),  but  whether  the  presence  of  a  waterfall  will 
give  rise  to  even  a  small  manufacturing  centre  depends 
on  several  other  conditions.  As  steam  makes  manufac- 
turing possible  now  where  it  was  not  possible  one  hun- 
dred years  ago,  and  as  the  coal  for  making  steam  can  be 
brought  great  distances  at  relatively  small  cost,  water  has 
largely  gone  out  of  use  as  a  power. 


FIG.    16. — A  COTTON   MILL  RUN   BY   POWER   FURNISHED   BY   A  GLACIAL 
WATERFALL. 

The  next  thing  in  importance  to  power  to  do  work  is 
some  material  to  work  with.  The  raw  products  should 
therefore  be  near  the  power  which  is  needed  for  manu- 
facturing, and  not  too  far  distant  from  the  markets  where 
the  finished  product  can  be  sold.  Some  raw  products 
and  some  forms  of  manufactured  goods,  from  their  value 
or  from  their  ease  of  transportation,  can  be  carried  long 
distances,  as,  for  instance,  in  the  case  of  cotton  brought 
from  Georgia,  Alabama,  or  Texas  to  Massachusetts  and 


MINING  CENTRES.  49 

Maine,  or  hides  from  South  America  to  the  tanneries 
and  shoe  factories  of  Massachusetts.  In  other  cases  the 
raw  products  cannot  be  transported  long  distances,  and 
the  manufacturing  must  be  done  close  to  the  region  of 
production.  For  instance,  iron,  which  is  very  heavy, 
and  which  may  contain  more  than  a  third  waste  as  it  is 
brought  from  the  mine,  must  be  prepared  for  market 
close  to  the  mines  from  which  it  is  secured,  so  as  to  save 
the  cost  of  transportation.  Pittsburg,  Pennsylvania,  is 
an  excellent  example  of  such  a  centre  near  to  the  iron 
mines.  On  the  other  hand,  some  small  towns  in  Georgia 
and  Alabama,  at  a  distance  from  one  or  more  of  the  three 
things  necessary  in  iron  making — i.e.,  raw  iron,  coal,  and 
limestone — never  grew  as  their  founders  had  hoped. 

Mining  Centres. — In  considering  mining  we  shall  use 
the  term  in  a  large  way,  to  include  all  the  different  forms 
of  getting  valuable  mineral  and  rock  materials  from  the 
earth.  We  must  therefore  consider  quarrying,  boring 
for  oil,  for  water,  for  natural  gas,  the  digging  of  clay  and 
sand,  the  washing  of  gravels  for  gold,  etc.,  as  different 
forms  of  mining.  In  each  case  the  industry  is  established 
at  a  certain  place,  because  there  the  earth  contains  valu- 
able material  to  be  secured  by  the  necessary  labor.  The 
character  of  the  rocks  at  the  surface  of  the  earth,  or 
immediately  beneath  the  surface,  is,  then,  the  funda- 
mental thing  that  determines  the  location  and  success  of 
mining.  As  a  matter  of  fact,  a  great  proportion  of  the 
valuable  mines  of  the  world  are  found  in  high  and  rugged 
mountainous  countries,  for  the  reason  that  the  rocks  that 
usually  make  mountains  contain  more  precious  material 
than  any  other  kinds  of  rocks. 

Therefore  we  expect  mines  to  be  found  largely  in  places 
that  offer  no  other  inducements  for  men  to  make  their 
4 


50  A   READER   IN   PHYSICAL   GEOGRAPHY. 

homes ;  that  is,  where,  from  the  character  of  the  rocks, 
the  small  quantity  of  the  soil,  and  the  steep  slopes,  the 
more  common  features  are  forests,  often  inhabited  by  wild 
animals.  The  rocks  of  Manhattan  Island,  especially  in 
its  higher  parts,  are  full  of  minerals  of  interest  to  the  col- 
lector of  minerals,  and  illustrate  very  well  the  general 


PIG.    17.— NOME,    A   MINING   TOWN   IN  ALASKA.        THE    GOLD    IS   FOUND   IN 
THE   BEACH    GRAVELS. 

relation  between  hard  rocks,  hilly  or  rugged  country,  and 
materials  of  value  in  the  rocks.  If  we  should  go  to  the 
granite  quarries  of  Cape  Ann  or  Quincy,  Massachusetts, 
we  would  find  a  rough,  rugged,  infertile  country,  in  gen- 
eral features  similar  to  the  regions  in  Colorado  from  which 
come  such  vast  quantities  of  precious  metals.  We  may 
thus  very  rightly  conclude  that,  as  a  rule,  mines  are  not 


MINING   CENTRES. 


very  accessible,  and  that  the  cost  of  transportation  of  the 
ores  is  great.  Hence  the  need  of  a  large  city  as  near  to 
the  mines  as  possi- 
ble, to  which  the 
products  of  the 
mines  may  be  sent 
for  refining  and 
shipment,  and  from 
which  supplies  may 
be  secured  by  the 
miners.  Denver, 
Colorado,  at  the 
eastern  foot  of  the 
Rocky  Mountains, 
is  an  excellent  ex- 
ample in  this  coun- 
try of  such  a  mine- 
made  town.  The 
cities  like  Nome 
(see  Fig.  17)  and 
Dawson  City  that 
have  lately  sprung 
up  in  Alaska,  be- 
cause of  the  find- 
ing of  gold  in  the 
gravels  of  the  Yu- 
kon country,  are 
other  illustrations 
of  mining  centres 
hav  i  n.g  all  the 
characteristics  of  busy  and  populous  mining  towns. 

Those  materials  that  are  secured  from  the  earth  in  a 
gaseous  or  liquid  condition,  such  as  oil,  gas,  and  artesian 


FIG.  IS. — AN  ARTESIAN  WELL  IN  SOUTH  DA- 
KOTA, THROWING  A  STREAM  OF  WATER 
TO  A  HEIGHT  OF  NINETY-SEVEN  FEET. 


$2  A   READER   IN   PHYSICAL   GEOGRAPHY. 

water  (see  Fig.  18),  are  not  necessarily  found  in  such  rough 
country  as  are  the  ores  and  rocks  considered  above.  Yet 
here  again  it  is  the  character  of  the  rocks  and  the  rock  con- 
tents that  determines  the  location  of  the  mining  centre. 
The  manufacturing  of  these  products  may  be  carried  on 


FIG.    19.— CLAY  FIELDS  AT   HAVERSTRAW,  NEW   YORK,  SHOWING  METHOD 
OF    QUARRYING    CLAY    FOR    BRICKS. 

near  the  place  where  they  are  dug,  so  that  a  city  or  town 
established  in  such  a  region  would  be  in  part  a  mining 
and  in  part  a  manufacturing  centre.  This  is  true  in  a 
number  of  places  in  New  Jersey  and  New  York  (see  Fig. 
19),  where  the  clays  for  bricks  are  manufactured  close  to 
the  pits  from  which  they  are  secured. 


FISHING  AND   HUNTING   CENTRES.  53 

Fishing  and  Hunting  Centres.-^-In  some  places  along 
the  shores  of  our  oceans,  rivers,  and  lakes,  people  are 
gathered  together  in  large  cities  or  small  villages,  to  cure 
and  sell  the  fish  that  some  of  the  men  of  the  community 
have  caught  in  the  neighboring  waters  or  in  the  distant 
parts  of  the  ocean.  Sometimes  the  fish  is  sold  fresh, 
sometimes  it  is  cured  or  salted,  and  in  some  cases  it  is 
canned.  In  each  instance  the  centre  of  industry  is  deter- 
mined by  the  chance  for  fishing.  In  sea  and  lake  fishing 
a  good  harbor  is  a  necessity,  and  nearness  to  fishing 
grounds  is  another  important  need.  Hence  we  have 
Gloucester  and  Provincetown  (see  Fig.  20),  two  famous 
fishing  centres  on  the  coast  of  Massachusetts,  near  the  so- 
called  "  fishing  banks  "  of  the  neighboring  Atlantic.  In 
the  days  of  fishing  for  whales  by  sailing-vessels,  Nantucket 
and  New  Bedford,  Massachusetts,  were  also  fishing  centres 
known  the  world  over,  because  of  their  many  vessels  that 
went  on  long  whaling  trips  to  the  most  distant  part  of  the 
oceans. 

In  some  instances,  as  at  Portland,  Oregon,  the  fishing 
centre  is  a  great  manufacturing  centre,  where  the  fish,  in 
this  case  largely  salmon,  are  cured  and  canned  for  ship- 
ping to  all  parts  of  the  world.  Similarly  we  have  fishing 
centres  where  oysters  are  gathered,  as  in  Chesapeake 
Bay;  where  lobsters  are  caught,  as  along  the  coast  of 
Maine ;  where  small  food  fishes  are  caught,  as  in  the 
many  bays  along  our  northern  Atlantic  coast. 

In  each  case  the  centre  is  determined  in  its  position  by 
the  geographical  conditions  that  make  it  possible  to  carry 
on  fishing  better  there  than  elsewhere. 

Another  activity  commonly  associated  with  fishing  is 
hunting,  not  so  much  for  food  as  for  furs.  Men  hunt  for 
food  and  for  sport ;  but  the  former  is  done  by  savages  or 


SCENIC    CENTRES.  55 

by  men  who  are  exploring  a  new  country,  and  the  latter 
by  men  who  go  into  the  wilderness  for  a  time,  and  lead  a 
rough,  wandering  life  of  pleasure.  Hunting  for  furs  is 
an  occupation  in  many  of  the  almost  uninhabited  regions 
of  the  world,  as  in  northern  Canada,  Russia,  and  Siberia. 
Years  ago  the  famous  Hudson  Bay  Fur  Company  had 
many  forts  established  throughout  the  remote  regions  of 
Canada,  from  which  men  went  forth  on  solitary  expedi- 
tions for  furs,  or  at  which  the  furs  were  bought  from  the 
Indian  trappers  who  wandered  through  the  forests  seek- 
ing the  wild  animals.  Rarely  are  large  numbers  of  peo- 
ple gathered  together  at  one  place  for  hunting,  so  that 
we  cannot  speak  of  hunting  centres  as  large  and  per- 
manent villages.  Yet  hunting  is  the  occupation  of  many 
men  in  the  rough,  rugged,  mountainous  regions  where  no 
other  occupation  is  possible,  or  in  the  cold,  barren  coun- 
tries where  the  land  may  be  low  and  more  or  less  level, 
but  almost  inaccessible.  Thus,  again,  the  character  of 
the  country  as  to  slope  and  climate  determines  whether 
a  region  shall  be  the  home  of  wild  animals  or  of  men  — 
that  is  to  say,  the  geographical  conditions  determine 
where  hunting  centres  shall  be  found. 

Scenic  Centres. —  The  last  of  the  centres  of  life  for  civ- 
ilized men  that  we  need  to  consider  is  what,  for  lack  of 
a  better  term,  we  have  already  called  a  scenic  centre.  By 
this  is  meant  a  settlement  of  greater  or  less  size,  and  of 
more  or  less  permanency,  made  near  some  object  of  inter- 
est to  which  people  will  make  visits  from  great  distances. 
The  summer  resorts  near  New  York  City,  such  as  Coney 
Island,  Long  Branch,  etc.,  are  excellent  examples  of  one 
kind  of  such  scenic  centres.  Here,  during  the  season 
when  people  make  visits  to  the  seashore,  we  find  really 
large  cities  that  may  be  almost  depopulated  during  the 


56  A   READER   IN   PHYSICAL  GEOGRAPHY. 

cold  seasons.  There  are  many  forms  of  such  scenic 
centres,  some  of  which,  like  a  local  summer  resort,  attract 
only  people  from  a  short  distance ;  others,  like  Niagara 
Falls,  the  cafton  of  the  Colorado,  etc.,  may  be  known 
throughout  the  civilized  world.  The  most  important 
kinds  of  such  centres  are  shores  either  of  the  sea  or  of  a 


FIG.    21. — THE    GORGE    OF    THE   RHINE,    VIEWED    FROM    THE   UPLAND,    AND 
SHOWING    THE    LOCATION    OF    A    TOWN    AT   THE    BASE    OF    THE    CLIFFS. 

large  lake;  mountains,  like  the  Catskills  in  New  York  or 
the  White  Mountains  in  New  Hampshire ;  great  gorges 
or  caftons,  such  as  the  caflon  of  the  Yellowstone  in  the 
Yellowstone  National  Park,  the  gorge  of  the  Rhine  (see 
Fig.  21);  forests  with  their  game,  as  in  the  case  of  the 
Maine  woods  ;  rivers  and  lakes,  such  as  exist  in  the 
Adirondacks ;  falls  of  rivers,  such  as  the  Shoshone  Falls 


SUMMARY.  57 

in  Idaho ;  caverns,  such  as  Luray  in  Virginia,  Mammoth 
Cave  in  Kentucky,  Howe's  Cave  in  New  York;  springs, 
such  as  those  at  Saratoga  or  Avon,  New  York,  or  Colo- 
rado Springs,  Colorado ;  and  places  of  some  historic  inter- 
est, such  as  the  great  battle-fields  of  Lookout  Mountain, 
Chickamauga,  and  Missionary  Ridge,  in  Georgia  and 
Tennessee. 

In  almost  every  case  the  underlying  cause  of  an  interest 
sufficient  to  attract  people  from  great  distances  is  some 
object  that  has  a  geographical  reason  for  being.  Nearly 
all  the  illustrations  that  I  have  given  have  been  geo- 
graphical, for  even  a  battle-field  has  its  geographical  rea- 
sons for  being.  It  was  the  geography  of  the  field  that 
made  it  a  favorable  place  for  the  holder,  and  hence  de- 
sired by  the  enemy.  The  strategic  position  that  the 
other  side  covets  in  war  is  one  of  such  a  geographical 
character  as  to  be  easily  defended,  and  hence  of  great 
value  to  the  army  holding  it.  The  battles  of  Bunker 
Hill,  of  Lookout  Mountain,  and  Manila  were  all  deter- 
mined in  their  place  by  the  topography  of  the  region. 

Summary. — Looking  back  for  a  moment's  review  of 
the  various  centres  we  have  considered,  and  of  the  causes 
that  have  largely  determined  them,  we  find  a  few  topics 
occurring  again  and  again.  Relief  and  slope,  together 
with  climate,  are  the  most  important  conditions.  The 
soils,  drainage,  etc.,  which  depend  largely  upon  the  topog- 
raphy, are  also  of  great  importance,  and,  together  with 
the  geographical  positions  of  the  great  water  bodies,  such 
as  the  seas  and  lakes,  and  the  form  of  the  coast  line,  are 
to  be  considered  as  important  geographical  reasons  influ- 
encing the  character  of  life  in  all  parts  of  the  world. 
These  topics,  then,  are  those  that  need  the  greatest  study 
if  we  are  to  understand  geographical  conditions,  and  it 


58  A    READER  IN   PHYSICAL   GEOGRAPHY. 

is  to  these  that  we  must  devote  the  larger  part  of  our 
attention. 

We  should  not,  however,  forget  that  all  the  riches  of 
the  world  were  here,  that  all  the  conditions  were  favor- 
able geographically  for  the  development  of  human  life, 
long  before  they  were  utilized.  We  speak  of  this  or  that 
geographical  feature  being  the  cause  of  some  great  step 
in  human  progress;  but  often  fail  to  remember  the  part 
that  man  has  played  in  taking  advantage  of  these  con- 
ditions. The  great  Mohawk  Valley  was  the  best  line  of 
communication  between  the  Atlantic  seaboard  and  the 
interior  of  the  United  States  long  before  the  Atlantic 
received  its  name,  or  the  United  States  were  dreamed 
of;  but  it  became  of  great  service  only  when  the  Euro- 
peans took  advantage  of  it.  Again,  we  hear  it  stated 
that,  given  coal  and  iron,  a  nation  must  be  great :  the  geo- 
graphical reasons  exist,  and  hence  there  must  be  advance- 
ment and  success.  This  is  true  in  England  and  in  those 
parts  of  the  United  States  where  coal  and  iron  have  been 
developed;  but  China,  with  its  great  riches  in  these  lines, 
is  not  one  of  the  great  commercial  and  industrial  nations 
of  the  world,  in  part  because  the  Chinese  have  not  taken 
advantage  of  all  the  important  geographical  conditions 
about  them.  They  have  lived  with  the  geographical  con- 
ditions, but  'have  not  been  helped  by  them,  or  at  least 
not  by  those  conditions  tQ  which  some  other  nations  owe 
so  much. 

The  geographical  conditions,  then,  are  the  underlying 
causes  of  human  progress  perhaps  in  a  greater  measure 
than  we  think;  but  they  become  important  in  human 
history  and  progress  only  when  man  takes  advantage  of 
them  and  develops  them. 


THE   ORIGIN   OF   LAND   FORMS. 

CHAPTER   VII. 

CHANGES    IN    THE    EARTH'S   CRUST. 

WE  have  seen  that  the  shape  and  slopes  of  the  land, 
or  the  topography  of  the  inhabited  parts  of  the  earth, 
have  had  an  important  part  in  determining  the  position 
and  character  of  the  several  forms  of  centres  we  have 
noted.  We  should  find  the  same  influence  of  topography 
on  life  were  we  to  study  plant  and  animal  life  in  their 
distribution  over  the  earth.  A  better  knowledge  of  the 
various  forms  of  land  and  their  importance  would  there- 
fore seem  valuable,  if  we  are  to  study  the  effects  of  topog- 
raphy with  any  care. 

In  order  to  know  any  form  of  topography  we  must 
become  so  thoroughly  acquainted  with  its  features  as  to 
recognize  it  and  be  able  to  name  it  when  we  meet  it  again, 
just  as  it  is  necessary  to  know  the  face  of  an  acquaintance 
before  we  can  be  sure  of  recognizing  him  in  a  crowd. 
We  must  remember,  however,  that  to  know  the  name 
is  not  sufficient;  we  may  know  the  name  of  a  plant, 
and  know  nothing  else  about  it.  After  we  know  the 
features  of  the  plant,  the  name  becomes  of  value  because 
it  allows  us  to  call  to  our  mind  the  whole  plant,  and  all 
its  important  features,  just  by  remembering  the  name. 
So  in  our  study  of  the  earth  we  must  have  a  knowledge 


60  A   READER   IN   PHYSICAL   GEOGRAPHY. 

of  the  meaning  of  the  shape  we  are  studying  before  we 
give  it  a  name. 

Thorough  acquaintance  with  any  form  of  topography 
and  with  its  name  does  not  mean  that  we  shall  see  every 
bit  of  topography  in  the  world.  That,  of  course,  is  an 
impossibility.  We  may,  however,  know  the  more  com- 
mon forms  which  are  to  be  found  over  the  earth,  and 
have  in  mind  at  least  some  one  good  illustration  of  each 
form  we  study. 

Such  a  study  of  the  forms  of  the  earth  can,  I  think, 
best  be  begun  through  considering  the  more  important 
ways  in  which  topography  is  being  made  and  changed  by 
the  earth  forces  that  are  at  work  about  us  all  the  time. 

Permanency  of  Land  Forms. — The  suggestion  that 
the  forms  of  the  earth  are  being  made  may  be  rather  sur- 
prising to  some  of  us  who  have  a  way  of  looking  upon 
the  features  of  the  earth  as  fixed  and  unchanging.  We 
commonly  speak  of  the  "  everlasting  hills  "  ;  but  the  evi- 
dence of  our  daily  experiences  would  tell  us,  did  we  stop 
to  observe,  that  changes  are  going  on  constantly,  and  that 
the  hills  are  far  from  being  everlasting.  For  instance, 
there  are  several  hills  in  Boston  Harbor,  Massachusetts, 
that  are  disappearing  very  rapidly  under  the  attacks  of 
the  ocean  waves,  and  it  will  take  but  a  few  hundred  years 
to  remove  them  entirely,  as  many  others  in  the  same 
region  have  been  removed  in  times  gone  by.  (See 

Fig.   22.) 

Instead  of  looking  upon  the  features  of  the  earth  as 
fixed,  it  would  be  far  nearer  the  truth  to  think  of  them 
as  changing  rapidly,  like  the  laughs  and  frowns  of  a  child. 
From  our  standpoint,  perhaps,  the  forms  of  the  earth  do 
many  of  them  seem  fixed  and  permanent,  for  our  lives 
are  short,  and,  except  in  rare  cases,  we  can  see  but  little 


PERMANENCY   OF   LAND   FORMS.  6 1 

change  in  the  earth  in  a  lifetime.  The  forces  of  the  earth 
work  on  a  large'scale  all  the  time,  and,  though  they  work 
very  slowly,  in  the  course  of  time  they  accomplish  large 
results.  Indeed,  the  larger  forms  of  the  earth  must  change 
with  as  great  rapidity,  from  the  earth's  standpoint,  as  do 
the  little  sand  and  mud  forms  in  the  wayside  mud  puddle 


FIG.  22. — A  HILL  IN  BOSTON  HARBOR  BEING  REMOVED  BY  THE  WAVES. 
THE  LARGE  BOULDERS  IN  THE  FOREGROUND  ARE  TOO  HEAVY  FOR 
THE  WAVES  TO  MOVE. 

of  a  summer  shower  from  our  standpoint.  Occasionally 
there  is  a  sudden  and  large  change,  such  as  when  Sandy 
Hook  was  separated  from  the  mainland  in  a  great  storm 
a  few  years  ago,  or  when  there  is  a  great  landslide,  such 
as  that  which  occurred  at  Amalfi,  Italy,  in  December, 
1899,  when  a  hotel  and  a  large  amount  of  rock  suddenly 
slid  into  the  sea. 


62  A   READER  IN   PHYSICAL   GEOGRAPHY. 

Such  a  way  of  looking  at  the  earth  features,  as  the 
results  of  great  but  slow-acting  forces,  gives  one  the  feel- 
ing of  great  power,  and  makes  one  full  of  awe,  as  when 
we  see  a  quietly  moving  but  almost  irresistible  machine 
slowly  but  surely  move  a  great  weight  or  cut  up  a  thick 
bar  of  iron.  Indeed,  we  soon  come  to  look  at  the  earth 
as  being  almost  a  living  thing,  like  ourselves,  doing  work 
and  changing  as  'the  years  go  on.  The  sea  wave,  the 
running  brook,  the  moist  air,  and  the  ice  all  have  a  new 
interest  when  we  look  at  them,  not  simply  as  objects  on 
the  earth  to  be  noted  and  described  merely,  but  as  great 
forces  doing  their  part  of  the  work  of  the  world,  and,  as 
we  shall  see,  usually  to  our  benefit. 

The  features  of  the  earth,  the  hills  and  valleys,  the 
mountains  and  plains,  as  we  now  see  them,  are  but  the 
results  of  the  work  of  the  great  earth  forces  acting  on  the 
rock  masses  of  the  earth,  just  as  the  statue  is  a  form 
made  by  the  force  of  man's  will  and  hand  out  of  marble 
or  granite  or  clay. 

In  studying  the  changing  forms  of  the  earth,  then,  we 
have  three  things  to  consider:  the  materials  on  which 
the  earth  forces  work,  the  manner  in  which  the  forces 
work,  and  the  results — i.e.,  the  forms  themselves. 

The  Materials  of  the  Earth's  Crust. — We  have  already 
seen  that  the  solid  framework  of  the  earth  is  made  of 
rocks,  and  that  the  rocks  contain  much  air  and  water, 
even  at  great  depths.  It  is  not  enough,  however,  simply 
to  say  that  the  earth,  and  particularly  the  earth's  crust, 
is  made  of  rocks,  as  though  all  rocks  were  alike  in  char- 
acter and  were  changed  in  form  by  the  forces  of  the 
earth  with  equal  ease.  It  is  not  necessary  for  our  pur- 
pose that  we  study  the  rocks  and  learn  their  names,  and 
the  name  and  proportion  of  all  the  materials  that  go  to 


THE    MATERIALS   OF  THE   EARTH  S   CRUST.  63 

make  up  any  given  rock,  for  such  a  study  is  more  for  a 
course  in  mineralogy  than  one  in  geography. 

For  our  purpose  we  may  say  that  there  are  two  great 
series  of  rocks,  each  with  many  varieties,  the  first  being 
the  rocks  that  appear  in  layers  or  strata,  and  known  as 
stratified  rocks  (see  Fig.  23);  and  the  second,  those  that 


tfiG.  23.— A  SERIES  OF  LAYERED  OR  STRATIFIED  ROCKS  BESIDE  THE 
GENESEE  RIVER  IN  NEW  YORK  STATE.  THE  WHITE  LAYER  IS  SEV- 
ERAL FEET  THICK. 

occur  in  great  masses  without  much  apparent  internal 
arrangement  of  the  materials,  which  we  may  call  crystal- 
line rocks.  The  stratified  rocks  have  mostly  been  made 
from  the  accumulation  of  deposits  of  sand,  clay,  and 
other  materials  in  some  great  body  of  water,  just  as  now 
we  can  see  the  sands  accumulating  on  the  seashore  in 
layers.  The  common  varieties  of  stratified  rocks  are 


64  A   READER  IN   PHYSICAL  GEOGRAPHY. 

sandstones,  which  are  but  stratified  sand;  slates,  which 
are  solidified  mud  ;  and  limestones,  which  are  mostly  made 
of  the  shells  of  animals  laid  down  in  mud  as  the  animals 
have  died,  just  as  we  may  see  them  now  accumulating 
in  the  mud  of  flats  from  which  clams  are  dug,  or  on  the 
sandy  or  muddy  bottom  where  oysters  grow.  A  certain 
kind  of  reddish  sandstone  is  much  used  for  buildings, 
especially  in  our  brownstone-front  houses;  slates  were 
formerly  used  by  almost  all  children  in  school,  but  are 
now  going  out  of  use  for  this  purpose,  though  they  still 
are  often  used  for  roofs.  Limestone  is  sometimes  em- 
ployed for  buildings,  as  in  many  large  white  buildings,  like 
Columbia  University  in  New  York  City  and  the  Brook- 
lyn Institute  in  Brooklyn.  Certain  forms  of  limestones 
known  as  marbles  are  largely  used  for  decorative  pur- 
poses in  houses  and  for  statuary.  There  are  many  vari- 
eties of  sandstone,  slate,  and  limestone,  varying  in  color, 
in  size  of  particles,  or  in  some  other  way,  and  the  thickness 
of  the  layers  may  vary  from  a  fraction  of  an  inch  to  several 
feet.  We  thus  speak  of  thin-bedded  or  thick-bedded 
stratified  rocks,  and  the  thickness  of  the  layers,  or  strata, 
is  a  very  important  matter  in  determining  the  kind  of 
topography  a  certain  rock  will  make. 

Crystalline  rocks  may  be  grouped  into  two  great  classes, 
in  each  of  which  there  is  an  almost  infinite  number  of 
varieties:  i.e.,  those  that  have  been  formed  at  a  great 
depth  in  the  earth,  and  are  known  as  plutonic  rocks,  of 
which  granite  (largely  used  for  paving  stones)  is  an  ex- 
ample ;  and  those  that  have  been  formed  on  or  near  the 
surface  of  the  earth,  and  are  known  as  volcanic  rocks,  of 
wrhich  the  rocks  of  the  Palisades  of  the  Hudson,  and  of 
the  Watchung  Mountains,  New  Jersey,  are  good  examples. 
As  the  name  signifies,  crystalline  rocks  are  made  of  crys- 


STRONG  AND    WEAK    ROCKS.  65 

tals,  and  were  once  in  such  a  fluid  condition  that  crystals 
could  form.  They  are  sometimes  known  as  igneous  rocks, 
because  they  have  once  been  heated.  The  crystals  may 
be  so  small  as  to  be  invisible  to  the  naked  eye,  or  they 
may  be  so  large  as  to  give  the  rock  a  coarse,  granular 
appearance. 

Strong  and  Weak  Rocks. — Each  of  the  several  vari- 
eties included  in  either  great  group  of  rocks  is  affected 


FIG.     24. — A    RIDGE    AT    CANON     CITY,     COLORADO,    SHOWING    EFFECT    OF 
STRONG   ROCKS   IN    MAKING   RELIEF.  * 

somewhat  differently  by  the  erosive,  or  wearing,  forces  of 
the  earth ;  but  certain  groups  as  a  whole  are  acted  on  in 
one  way,  and  certain  others  in  another.  In  general,  we 
may  speak  of  those  rocks  resisting  the  forces  acting  upon 
them  as  hard  or  strong  rocks,  as  strong  gives  us  the  idea 
of  might  that  the  rock  shows  by  its  resistance.  Granites, 
many  sandstones,  and  the  trap  rock  of  the  Palisades  are 
excellent  examples  of  such  strong  rocks.  Strong  rocks 
stand  up  in  ridges  or  heights,  so  that  we  may  speak  of 
5 


66  A  READER  IN  PHYSICAL  GEOGRAPHY. 

strong  rocks  as  ridge  makers,  because  of  the  failure  of  the 
forces  to  wear  them  away.     (See  Fig.  24.) 

On  the  other  hand,  there  are  the  softer,  weak  rocks 
that,  yielding  easily  to  the  forces  acting  upon  them,  tend 
to  make  lowlands.  (See  Fig.  25.)  Certain  varieties  of 
mud  rocks  and  most  forms  of  limestone  are  usually  weak, 
so  that  we  may  expect  these  rocks  to  be  found  largely  in 
valleys,  while  their  stronger  neighbors  are  found  on  the 


t'IG.  25.- — A  CLIFF  AND  LOWLAND  IN  ARIZONA,  SHOWING  STEEP  SLOPES 
MADE  ON  STRONG  ROCKS,  GENTLE  SLOPES  ON  WEAKER  ROCKS,  AND 
VERY  FLAT  SLOPES  ON  WEAKEST  ROCKS. 

uplands.  This  is  not  an  absolute  rule,  however,  as  some- 
times sandstones  are  weak  and  limestones  are  strong;  but 
it  is  generally  true. 

The  test,  then,  of  whether  a  rock  is  weak  or  strong  is 
its  behavior  in  reference  to  the  forces  that  tend  to  wear 
it  away.  As  these  forces  are  some  of  them  acting  every- 
where all  the  time,  no  rock  exposed  on  the  surface  of  the 
earth  can  escape  a  test  of  its  strength.  We  can  see  the 
work  going  on  if  we  but  observe  carefully,  and  we  can 
see  the  results  in  our  topography.  The  forces  that  we 


HOW   THE   EARTH   WEARS  AWAY.  67 

can  see  in  operation  immediately  about  us  are  not  the 
only  erosive  forces  of  the  world ;  but  they  are  the  most 
important,  and  a  study  of  them  and  their  work  will 
enable  us  to  understand  great  and  distant  topographic 
features  of  the  world,  such  as  the  peaks  of  the  Alps  or 
the  Rocky  Mountains,  the  Ganges  Plain,  or  the  Valley 
of  the  Amazon.  Let  us  therefore  look  about  us  and  see 
what  forces  there  are  at  work,  and  some  of  their  more 
important  effects. 

How  the  Earth  Wears  Away. — We  have  already  seen 
that  three  great  forms  of  matter  make  up  the  world,  and 
we  have  found  the  solid  rocks  of  the  earth  to  be  the 
material  exposed  to  the  sculpturing  of  the  erosive  forces. 
As  a  force  implies  movement,  we  should  naturally  ex- 
pect that  the  more  movable  parts  of  the  earth,  the  air 
and  the  water,  would  be  the  great  earth-sculptors,  and  in 
this  we  are  right.  We  cannot,  however,  treat  these  two 
forces  alone;  we  must  treat  of  four  forms  of  work,  be- 
cause water  may  erode  in  any  of  three  forms,  as  liquid 
water,  as  solid  ice,  or  as  invisible  gaseous  vapor.  Water 
working  in  the  form  of  vapor  works  with  and  in  the  at- 
mosphere, and  we  will  consider  it  in  association  with  the 
atmosphere. 

Again,  the  liquid  water  may  be  divided  into  that  which 
stands  at  a  constant  or  nearly  constant  level  in  some 
great  lake  or  ocean,  and  that  which  is  continually  run- 
ning down  toward  the  ocean,  as  in  our  rivers  ;  standing 
water  works  in  one  way,  and  running  water  in  another, 
so  that  we  must  consider  them  separately.  Finally  we 
have  solidified  water,  or  ice,  working  as  frost,  as  ice  on 
our  lakes,  rivers,  and  seashores,  or  in  the  great  glaciers 
of  such  regions  as  Alaska  and  Switzerland.  Thus  we 
have  four  great  erosive  forces  to  consider,  each  in  some 


68  A   READER  IN   PHYSICAL  GEOGRAPHY. 

detail:  viz.,  the  atmosphere,  running  water,  standing 
water,  ice. 

We  must  look  at  these  forces  not  simply  as  erosive 
forces,  loosening  the  rock  particles,  but  we  must  study 
all  the  different  features  of  their  work.  Were  the  rocks 
simply  worn  away,  and  the  particles  separated  and  loos- 
ened and  left  where  they  were  originally  found,  but  little 
change  in  the  forms  of  the  earth  could  be  brought  about. 
In  order  to  bring  about  a  change,  the  loosened  material,  or 
detritus,  must  be  removed,  and  after  a  long  or  a  short 
journey  finally  left  somewhere  else.  The  rock  left  in  the 
hills  that  has  not  been  removed  will  make  one  kind  of 
form,  and  the  material  carried  to  a  distance  and  dropped 
will  make  another,  so  that  any  erosive  force  changes  the 
form  of  the  earth  on  which  it  works  in  two  ways,  by 
removing  from  one  place  and  building  at  another,  just  as 
a  sculptor  makes  from  a  block  of  marble  both  a  statue 
and  a  pile  of  chips  formed  from  the  pieces  he  chips  off 
and  throws  away. 

We  have,  then,  three  kinds  of  work  to  consider  under 
each  of  these  forces:  the  work  of  erosion  or  of  loosening 
the  particles,  that  of  removing  the  bits,  and  that  of 
depositing  or  dropping  them  in  a  new  place.  As  the 
atmosphere  is  the  most  important  and  widespread,  and 
the  one  force  that  every  one  can  see  at  work,  we  shall 
consider  that  first. 


CHAPTER   VIII. 
THE   WORK   OF   THE   ATMOSPHERE. 

Weathering. — The  atmosphere — now  cold,  now  hot, 
now  dry,  now  wet — is  always  present  and  in  contact  with 
the  whole  surface  of  the  earth.  These  changes  of  con- 
ditions give  us  our  varieties  of  weather.  We  all  know 
how  strong  an  influence  the  weather  has  upon  our  feel- 
ings— a  cool,  bracing  day  giving  us  energy,  a  hot,  muggy 
day  making  us  languid  and  lazy.  That  the  effect  of  the 
weather  may  be  seen  as  well  as  felt  is  evident  in  the 
case  of  hardened  sailors,  whom  perhaps  we  speak  of  as 
'*  weather-beaten  old  salts."  We  may  speak,  too,  of  the 
weather-beaten  shingles  of  an  old  house,  meaning  thereby 
that  the  sap  and  strength  of  the  shingles  have  been  taken 
away  through  the  influence  of  the  weather;  that  the 
wood  is  gray  and  punky,  and  perhaps  moss-covered. 
The  shingle  is  light  in  weight  as  compared  with  a  new 
shingle  of  the  same  size,  and  the  evidence  is  strong  that 
something  has  gone  from  the  wood.  That  "  something  " 
has  been  largely  carried  away  in  solution  in  the  moisture 
of  the  air,  as  salt  is  carried  away  in  spray  from  the  ocean. 
In  a  similar  way  the  soluble  parts  of  rocks  and  all  mate- 
rials exposed  to  the  atmosphere  are  slowly  carried  away 
by  the  moisture  of  the  air.  In  our  cities  we  see  the  effects 
of  such  destructive  work  of  the  atmosphere  in  the  dis- 
colored and  crumbly  brownstone  fronts,  and  in  New  York 
City  we  have  a  splendid  example  of  weathering  in  "  Cleo- 
patra's Needle,"  which  stood  comparatively  unchanged 


70  A   READER   IN   PHYSICAL   GEOGRAPHY. 

for  ages  in  the  dry  air  of  Egypt.  It  is  now  crumbling 
away  so  rapidly  in  our  moist  and  changeable  climate  that 
it  has  to  be  protected  from  the  weather  by  a  transparent 
coating  that  keeps  the  air  from  the  rock. 


FIG.  26. — AN  EROSION  COLUMN  AT  MANITOU,  COLORADO,  MADE  BY 
WEATHERING  OF  LAYERED  SANDSTONE  OF  DIFFERENT  DEGREES  OF 
STRENGTH. 

The  atmosphere  in  all  parts  of  the  world  contains  some 
moisture,  and  thus  rocks  will  be  decayed  or  weathered 
everywhere,  but  not  with  equal  rapidity,  the  rate  being 
slower  in  dry  regions  such  as  the  Sahara  or  our  Great 
American  Desert,  and  more  rapid  in  moist  countries. 
We  should  therefore  expect  weak  rocks  in  moist  coun- 


WEATHERING.  71 

tries  to  be  worn  down  with  the  greatest  rapidity,  and 
strong  rocks  in  dry  countries  to  wear  th-e  most  slowly. 
All  parts  of  the  same  rock  are  not,  however,  equally 
strong,  and  the  weaker  parts  are  dissolved  or  etched 
away,  leaving  the  harder  particles  projecting,  so  that  a 
weathered  rock  is  usually  rough.  Owing  to  differences 
of  strength  rock  masses  are  sometimes  eroded  into  fan- 
tastic shapes.  (See  Figs.  26  and  27.)  A  polished  granite 


FIG.     27. — A     SERIES     OF     EROSION     BOULDERS     IN     ARIZONA.        NOTE     THE 
SLENDER    PEDESTALS    ON    WHICH    CERTAIN    BOULDERS    REST. 

stone  or  monument  will  thus  lose  its  polish  and  smooth- 
ness in  the  course  of  time. 

The  rate  of  weathering  depends,  again,  upon  the  ease 
with  which  the  weathering  agents  can  penetrate  the  rock, 
and  the  amount  of  surface  exposed  to  the  processes  at 
work.  Any  force  that  loosens  or  makes  finer  our  solid 
rocks  gives  a  chance  for  water  and  moisture  to  penetrate, 
and  makes  their  destruction  more  rapid.  Water  freezing 
in  the  minute  cracks  which  are  found  in  nearly  all  rocks 
breaks  the  rocks  apart  and  makes  them  finer.  Roots  of 


72  A   READER   IN   PHYSICAL  GEOGRAPHY. 

trees  and  plants,  burrowing  animals  like  the  ground  hog, 
prairie  dog,  moles,  and  common  angle-worms,  are  thus 
very  active  assistants  in  the  process  of  rock  decay. 

Each  splitting  into  finer  fragments  exposes  more  sur- 
face to  attack,  and  hence  assists  the  rate  of  weathering, 
or  erosion.  Take  a  block  of  marble  having  six  faces, 
each  one  foot  by  one  foot :  this  block  contains  one  cubic 
foot,  and  has  six  square  feet  of  surface  exposed  to  possi- 
ble weathering  and  decay.  Now  cut  it  into  blocks  each 
one  inch  by  one  inch,  and  we  have  1,728  pieces,  each 
containing  a  cubic  inch;  but  each  of  these  will  have  six 
square  inches  of  surface,  and  all  together  seventy-two 
square  feet  of  surface.  By  dividing  into  cubic  inches  we 
have  increased  the  surface  exposed  to  twelve  times  its 
original  quantity.  You  can  thus  readily  see  that  if  you 
divide  the  original  cubic  foot  into  pieces  as  big  as  the 
head  of  a  pin,  which  would  be  a  large  fragment  in  some 
kinds  of  soil,  you  will  have  increased  the  amount  of  sur- 
face so  much  that  one  could  not  appreciate  it  if  ex- 
pressed in  figures. 

There  are  other  signs  of  weathering  besides  the  soften- 
ing and  crumbling  of  the  rocks.  When  rocks  become 
discolored  they  grow  red  or  brown  or  gray,  and  then  give 
a  foothold  to  the  low  forms  of  plants  known  as  lichens, 
that  cover  our  hard  rock  ledges  in  moist  regions.  It  is 
largely  from  the  detritus  weathered  from  the  solid  rocks 
that  our  soil  is  made,  upon  which  nearly  all  vegetable  and 
animal  life  depends.  A  fine  soil  thus  is  the  most  fertile, 
because  plants-can  get  food  from  it  most  readily.  .  Weath- 
ering also  rounds  off  corners,  and  a  weathered  pebble, 
rock,  doorstone,  or  board  loses  its  angularity  and  becomes 
rounded  and  subdued  in  outline. 

As  destruction  proceeds,  we  should  therefore   expect 


THE   EFFECTS   OF   GRAVITY.  73 

our  cliffs  and  high  ridges  to  become  less  sharp  and  less 
craggy.  Such  a  contrast  of  outline  and  color  is  very 
clearly  shown  by  comparing  a  weathered  piece  of  trap 
rock  from  the  Palisades  of  the  Hudson  with  one  just 
broken  away.  The  weathered  piece  is  brown  and  some- 
what rounded,  it  feels  soft,  and  the  particles  are  loosened 
on  the  surface.  The  other  piece  is  dark  green  and  the 
edges  are  sharp — indeed,  so  sharp  that  they  cut  like  a 
piece  of  glass.  It  will  also  ring  like  a  piece  of  iron  when 
struck  by  a  hammer. 

Were  the  materials  loosened  from  the  rocks  by  the 
processes  I  have  briefly  sketched  to  remain  where  they 
had  originated,  all  our  solid  rocks  would  be  covered  with 
a  thick  layer  of  their  own  detritus,  that  would  be  soft  and 
probably  reddish,  for  all  rocks  are  apt  to  decay  to  a  red, 
rusty  soil,  because  of  the  presence  of  iron.  Indeed, 
weathering  is  but  a  kind  of  rusting  that  is  so  common  in 
daily  life.  Over  a  large  part  of  the  world  such  red  soil 
has  accumulated  in  some  cases  to  a  depth  of  several  hun- 
dred feet,  so  that  the  solid,  unweathered  rock  rarely 
appears  at  the  surface. 

The  Effects  of  Gravity. — There  are,  however,  agents 
at  work  in  most  regions  removing  the  detritus,  and  carry- 
ing it  perhaps  to  a  great  distance  from  the  place  of  its 
origin.  Any  agent  which  is  capable  of  setting  things  in 
motion  helps  carry  the  detritus  worn  from  the  land  down 
toward  the  sea,  into  which  it  finally  comes,  and  in  which 
it  may  accumulate  to  great  depths.  The  wind  carries  its 
share  in  the  form  of  dust ;  the  rivers  carry  very  large 
loads  as  sand  or  gravel  or  silt ;  the  ocean  removes  a  cer- 
tain amount  by  the  undertow  of  the  waves  and  the  tides, 
and  we  again  know  it  as  gravel  or  pebbles.  .  The  everlast- 
ing pull  of  gravity  draws  downward  any  loosened  rock 


74  A   READER  IN   PHYSICAL  GEOGRAPHY. 

materials,  and  if  a  large  mass  from  some  cliff  or  moun- 
tain moves  at  one  time,  we  say  we  have  an  avalanche  or 
landslide  (see  Fig.  28)  ;  the  rocks  and  soil  are  full  of 
water,  and  in  most  regions  the  soils  on  the  hillsides 
slip  or,  perhaps  better,  creep  slowly  downward  because 
the  particles  are  lubricated  so  that  they  slip  over  each 
other  easily  < 


FIG.     28. — A     SERIES    OF     HUGE     LANDSLIDES     AT    BASE     OF     AN     ARIZONA 

CLIFF. 

Talus  Slopes. — One  of  the  best  places  to  see  the  work 
of  gravity  is  on  the  face  of  some  cliff  like  the  Palisades. 
Here  we  find  at  the  base  of  the  cliff  a  steeply  sloping 
bank  of  rock  detritus,  very  evidently  derived  from  the 
cliff  itself,  that  is  continually  being  increased  by  addi- 
tions from  above.  The  materials  are  of  all  sizes,  and 
slip  and  roll  easily  under  the  feet  as  one  climbs  toward 
the  top.  Such  an  accumulation,  to  be  found  usually  at 
the  foot  of  any  weathering  cliff,  is  known  as  a  talus.  (See 


TALUS  SLOPES.  75 

Fig.  29.)  If  it  occur  in  a  moist  country,  and  if  the 
materials  have  remained  long  enough:  in  one  position  so 
that  a  soil  layer  has  had  a  chance  to  accumulate,  the 
talus  may  be  covered  with  trees. 


FIG.  29. — A  TALUS  SLOPE  AT  BASE  OF  PALISADES.  NOTE  CLIFF  ABOVE 
TALUS,  AND  WOODED  CHARACTER  OF  PORTIONS  OF  TALUS,  SHOW- 
ING A  LONG  PERIOD  WITHOUT  MOVEMENT  OF  THE  PARTICLES. 

The  detritus  thus  started  downward. is  on  its  way  to 
the  sea,  the  lowest  place  on  the  earth's  surface  at  which 
it  can  accumulate,  and  the  goal  of  all  soil  and  detritus. 
Whatever  the  force  that  sets  the  loosened  material  in 
motion,  its  journey  to  the  sea  is  not  a  continuous,  but 


76 


A  READER  IN   PHYSICAL  GEOGRAPHY. 


an  interrupted  one.  As  the  messenger  boy  who  loiters 
by  the  way  to  play  with  his  companions  is  on  his  way  to 
his  destination  until  he  gets  there,  so  the  detritus  thus 
derived  from  the  land  is  on  the  way  to  the  sea  after  it 
once  starts,  even  though  we  find  the  pebbles  of  the  talus 
or  the  soil  apparently  stationary.  The  motion  is  slow 
but  sure. 

The  Wind. — The  method  thus  far  considered  is  not 


FIG.    30. — UNCUT     AND     CUT     SIDES     OF    A     SAND-BLASTED     PEBBLE     FROM 
CAPE   COD,    MASSACHUSETTS. 

the  only  way,  however,  in  which  the  air  loosens  mate- 
rials from  the  rocks.  The  wind,  which  has  been  sug- 
gested as  a  carrier  of  rock  detritus,  is  also  in  some  regions 
a  powerful  agent  of  erosion.  Some  of  us  have  had  our 
faces  cut  and  hurt  by  sleet  or  sand  or  dust  driven  by  the 
wind,  and  we  know  from  experience  that  the  wind  can 
erode,  not  by  itself  alone,  but  by  means  of  the  materials 
or  tools  it  carries  along.  In  some  regions  where  there  is 
much  drifting  sand,  each  particle  is  a  possible  chisel  to 


DUNES. 


77 


be  used  by  the  wind,  and  the  work  of  wind  erosion  is 
rapid  and  important.  On  sandy  shores  such  as  that  of 
Cape  Cod,  in  certain  parts  of  Colorado,  or  in  Arabia,  at 
all  of  which  excellent  examples  of  wind  work  have  been 
found,  the  moving  particles  of  sand  have  cut  and  even 
polished  the  exposed  surfaces  of  the  rocks.  (See  Fig. 
30.)  The  process  of  wind  erosion  is  employed  in  the 
making  of  ground  glass,  which  is  ordinary  glass,  one  side 


FIG.    31. — SAND   DUNES   AT   IPSWICH,    MASSACHUSETTS,    SHOWING   GENERAL 
ABSENCE    OF   VEGETATION. 


of  which  has  been  exposed  to  a  blast  of  sand  carried  by 
a  strong  forced  draft!  The  cut  and  ground  side  has  lost 
many  little  pieces  under  the  attack  of  the  wind-driven 
sand  chisels,  and  feels  rough  to  the  touch. 

Dunes. — The  manner  in  which  wind  carries  "light  par- 
ticles of  all  kinds,  and  particularly  the  fine  particles  of 
rock  that  we  call  dust,  is  well  known  from  experience. 
Go  to  a  sandy  seashore  on  even  a  very  quiet  day,  and 
close  to  the  surface  of  the  ground,  where  the  sand  is  dry, 


7»  A  READER  IN   PHYSICAL  GEOGRAPHY. 

you  will  see  a  thin  little  skimmering  of  sand  drifting 
along  quietly  with  the  wind.  The  sand  moves  on  until 
it  strikes  some  object,  perhaps  a  rock  or  a  pebble,  and 
then  a  little  of  it  stops  on  the  lee  side  of  the  obstruction. 
More  sand  follows,  and  accumulates  in  a  similar  manner 
until  great  sand-drifts,  very  much  like  snow-drifts,  are 
formed.  Such  sand-drifts  are  known  as  sand  dunes,  and 


FIG.  32. — AN  APPLE  ORCHARD  ONCE  BURIED  BY  SAND  DUNES  AT  IPSWICH, 
MASSACHUSETTS,  AND  NOW  BEING  REVEALED,  OWING  TO  REMOVAL 
OF  SAND. 

are  very  conspicuous  forms  in  some  parts  of  the  earth, 
particularly  in  deserts  like  the  Sahara  and  on  some  sea- 
shores. (See  Fig.  31.)  Small  dunes  may  be  seen  at  Far 
Rockaway  and  other  beaches  near  New  York  City,  and 
very  beautiful  examples  occur  at  Provincetown,  Massa- 
chusetts, at  the  southeastern  end  of  Lake  Michigan,  and 
at  many  other  places  that  might  be  mentioned.  Sand 
dunes  may  grow  to  the  height  of  a  hundred  feet  or  more, 


DUNES. 


79 


and  are  in  a  way  dangerous,  for  the  drifting  sand  may 
creep  over  and  cover  up  valuable  property.  In  one 
place  in  Massachusetts  an  apple  orchard  was  destroyed 
by  the  drifting  sand  (see  Fig:  32),  and  at  Provincetown  a 
keeper  of  the  dunes  is  elected  yearly  to  do  what  he  can 
to  keep  the  sands  from  blowing  by  making  vegetation 
grow  over  the  dunes,  and  to  protect  the  grass  cover  after 


FIG.    33. — A    VALLEY    IN    ARIZONA    NEARLY    FILLED    BY    DRIFTING    SAND. 
NOTE    THE   RLPPLED    SURFACE   AND    ABSENCE    OF   VEGETATION. 


once  it  is  grown.  Dunes  from  their  sandy  character  are 
very  barren,  and  it  is  only  with  great  difficulty  that  any 
vegetation  can  be  made  to  take  root.  Hence  dune  areas 
are  not  thickly  settled  regions  (see  Fig.  33),  being  more 
the  homes,  as  in  the  case  of  our  Eastern  dunes,  of  small 
birds  and  the  haunts  of  bird-hunters,  or  possibly  the  seat 
of  small  summer  resorts. 

Thus  we  see  that  wind-made   accumulations  of  sand 


80  A  READER  IN  PHYSICAL  GEOGRAPHY. 

may  make  very  large  and  important  topographic  features. 
In  a  similar  way  the  wind  in  certain  parts  of  the  world 
has  made  great  deposits  of  dust  known  as  loess  deposits. 
Such  accumulations  have  been  formed  in  China  to  a 
depth  of  more  than  a  thousand  feet. 


CHAPTER  IX. 

THE  WORK  OF  RUNNING  WATER. 

IF  we  were  to  go  to  a  freshly  ploughed  field  to  study 
the  work  going  on  there,  we  would  have  difficulty  in 
separating  that  which  is  being  done  by  the  atmosphere, 
by  gravity,  and  by  running  water.  The  weathering  by 
the  atmosphere  loosens  and  makes  finer  the  rock  parti- 
cles ;  gravity  gives  them  a  pull,  and  perhaps  carries  them 
a  little  way;  but  the  water  running  down  the  slope,  or 
creeping  through  the  soil,  is  the  great  agent  that  carries 
the  loosened  fragments  away.  Running  water  is  the 
force  that  we  should  be  able  to  recognize  as  the  most 
active  and  most  important  of  all.  If,  on  the  other  hand, 
we  should  go  to  a  forested  region,  or  to  one  covered  with 
vegetation  of  any  kind,  we  would  probably  see  but  little 
evidence  of  the  work  of  running  water,  as  most  of  the 
water  falling  as  rain  or  snow  would  soak  into  the  ground, 
and  creep  slowly  down  rather  than  run  quickly  to  the 
sea,  as  in  a  more  barren  country.  Hence  the  importance 
of  a  covering  of  vegetation  in  keeping  the  ground  from 
being  rapidly  worn  or  in  keeping  water  in  the  soil,  so 
that  the  rivers  will  not  have  seasons  of  flood  and  drought, 
but  be  furnished  water  slowly. 

Running  water  is  the  most  active  of  the  agents  of  ero- 
sion where  the  conditions  are  favorable.  With  a  weak 
rock,  steep  slopes,  and  a  large  volume  of  water,  necessarily 
running  quickly,  the  work  of  erosion  is  rapid  and  effec- 
tive. The  opposite  conditions  give  running  water  but 
6 


82  A   READER   IN   PHYSICAL   GEOGRAPHY. 

little  chance  to  be  effective  as  an  eroding  agent,  and  we 
find  it  doing  another  great  and  important  work. 

When  we  think  of  running  water  we  usually  think  of 
it  as  in  some  river  or  river  valley,  perhaps  some  valley 
that  we  know,  and  we  have  a  feeling  that  only  in  some 
large  stream  can  we  really  see  the  water  at  work.  As 
a  matter  of  fact,  however,  the  work  that  one  can  see  in 
a  large  stream  is  very  disappointing,  because  the  river  is 
not  eroding  rapidly,  and  because  the  river  valley,  which 
we  must  study  in  relation  to  the  river  within  it,  is  too 
large  to  study  as  a  whole,  or  even  to  see  at  a  glimpse. 
The  best  place  to  study  the  various  kinds  of  work  done 
by  running  water  is  in  some  wayside  stream  that  forms 
in  a  rainstorm,  works  rapidly,  and  ceasing,  leaves  the 
marks  of  its  work  on  the  surface  for  our  leisurely  exami- 
nation. 

The  Erosive  Work  of  Running  Water. — The  river 
valley,  as  well  as  the  river,  deserves  our  attention ;  for 
though  the  running  water  does  the  erosive  work,  it  is  in 
the  river  valley  as  a  whole  that  we  can  study  the  many 
different  features  due  to  river  work. 

The  atmosphere  and  the  river  must  be  studied  to- 
gether, because  they  work  together.  The  atmosphere 
and  gravity  loosen  the  rock  materials  and  bring  them 
down  to  the  streams,  but  the  streams  are  usually  the 
most  active  agents  in  removing  the  detritus.  Indeed,  the 
river's  work  is  more  that  of  a  carrier  of  the  detritus  de- 
rived from  the  land  than  that  of  an  eroding  agent.  Some- 
times the  river  is  likened  to  a  railway  train  that  receives 
and  carries  all  freight  delivered  to  it,  and  the  atmosphere 
and  gravity  to  the  farmers  who  prepare  the  freight  for 
shipping,  and  take  it  to  the  train. 

In  the  upper  portions  of  a  river  where  the  slopes  are 


THE   EROSIVE   WORK  OF   RUNNING   WATER.  83 

steep,  we  find  the  water  rolling  fragments  along,  hurling 
them  one  against  another,  and  against  the  sides  and  bot- 
tom of  the  channel,  thus  wearing  them  finer  and  finer, 
and  making  the  channel  deeper  and  deeper.  A  river  can 
roll  along  the  largest  particles  when  it  contains  the  most 
water.  Hence  the  rushing  torrents  formed  by  spring 


FIG.      34. — A      STREAM-BED      IN      THE      ADIRONDACK,       SHOWING      LARGE 
BOULDERS   THAT   CAN   BE   MOVED    ONLY   IN    TIME   OF    FLOOD. 

floods  can  carry  larger  and  more  rocks  than  the  withered 
summer  streams,  and  many  streams  show  us  in  summer 
a  floor  of  rounded  pebbles  that  were  in  active  motion 
earlier  in  the  season.  (See  Fig.  34.)  As  the  stream  thus 
cuts  its  channel  down,  it  brings  its  bottom  nearer  and 
nearer  to  the  level  of  the  sea,  so  that  the  slope  grows 
less,  and  the  river  less  powerful  as  an  eroding  agent.  At 
the  same  time  side  or  tributary  streams  cut  back  chan- 


84 


A   READER  IN   PHYSICAL  GEOGRAPHY. 


nels  into  the  banks,  thus  greatly  increasing  the  amount 
of  river  channels  in  a  region.     (See  Fig.  35.) 

As  it  cuts  lower,  the  head  of  the  river  creeps  farther 
and  farther  back,  thus  lengthening  the  stream.  This 
lengthening  of  the  stream  towards  its  head,  or,  as  we  may 


FIG.      35. — A     STREAM     IN     FLOOD,     SHOWING     UNDERCUTTING     OF     OUTER 
BANK    AND    DEVELOPMENT    OF    TRIBUTARY    CHANNEL. 

say,  headwards,  is  very  well  shown  in  a  clay  bank,  where 
we  find  the  upper  and  steeper  portions  of  the  bank  con- 
.tinually  falling.  (See  Fig.  36.)  The  material  thus  re- 
moved, and,  indeed,  all  material  that  comes  into  the 
water,  is  carried  along  by  the  stream  as  far  as  it  can  be, 
and  may  be  called  the  load  of  the  stream.  As  the  slope 
decreases,  the  size  of  the  particles  carried  by  the  stream 


THE   EROSIVE   WORK   OF   RUNNING   WATER.  85 

necessarily  grows  less  and  less,  for  its  carrying  power 
grows  less  and  less.  When  the  stream  no  longer  can 
carry  all  its  load,  we  say  it  is  overloaded,  and  when  over- 
loaded it  must  drop  that  part  of  its  load  that  is  carried 
with  the  greatest  difficulty;  that  is,  the  largest  and 


FIG.    36. — RAPIDLY    DEVELOPING   RIVER   CHANNELS   ON   A   NEBRASKA 

BLUFF. 

heaviest  particles  that  have  been  too  strong  to  be  worn 
much  smaller  with  the  battering  they  have  received  as 
they  have  journeyed  along.  As  we  go  down  stream,  the 
slope  grows  more  and  more 'gentle,  and  hence  the  parti- 
cles that  can  be  carried  grow  smaller  and  smaller,  until 
finally  they  float  along  in  the  water,  instead  of  being  rolled 
along  the  bottom.  The  particles  carried  along  by  the 


86  A   READER  IN   PHYSICAL    GEOGRAPHY. 

Hudson  are  seen  to  be  very  fine,  as  may  be  shown  by 
allowing  a  glass  of  Hudson  River  water  to  stand  undis- 
turbed until  its  detritus  has  had  time  to  settle.  It  is 
said  that  the  Mississippi  rarely  carries  a. particle  as  large 
as  a  pea  to  the  Gulf  of  Mexico;  but  the  quantity  of  fine 
materials  carried  is  enormous,  sufficient,  it  is  said,  in  a 
year  to  cover  an  area  a  mile  square  to  a  depth  of  more 
than  two  hundred  and  fifty  feet. 

The  detritus  thus  carried  along  by  a  stream,  and,  as 
we  shall  soon  see,  finally  deposited,  cannot  be  ignored 
in  considering  a  river  and  its  work.  Some  streams  roll 
their  loads  along  the  bottom,  and  are  clear;  in  other 
cases  the  load  is  floated  in  the  water  in  the  form  of  fine 
particles,  and  we  say  that  the  river  is  muddy;  in  still 
other  cases  there  is  little  visible  load,  yet  the 'load  exists, 
being  dissolved  in  the  water  as  sugar  may  be  dissolved 
in  water  without  coloring  it  in  the  least.  Thus  there 
is  no  perfectly  pure  water  in  any  stream,  no  water  free 
from  detritus  in  greater  or  less  abundance.  Hence  the 
detritus  is  as  much  a  part  of  the  stream  as  is  the  water; 
and  any  definition  of  a  river  that  does  not  include  the 
carried  load  tells  but  a  part  of  the  story,  and  is  inaccurate 
as  well  as  incomplete. 

Again,  we  usually  think  of  the  water  of  a  river  as  flow- 
ing down  a  definite  course  to  the  ocean.  Such  an  idea, 
however,  is  inaccurate,  as  appears  at  once  if  we  stop  and 
think  that  many  rivers  change  their  courses,  often  with 
great  suddenness,  as  happens  from  time  to  time  in  the 
Hwang-ho  of  China.  Again,  as  the  water  of  many  rivers 
in  deserts,  or  on  sandy  plains,  dries  up  or  disappears  in 
the  sand  long  before  the  level  of  the  sea  is  reached,  it 
is  very  incorrect  to  think  that  all  rivers  flow  into  the  sea. 
They  flow  toward  the  ocean — that  is,  down  hill — and  were 


THE   EROSIVE   WORK  OF   RUNNING   WATER. 


FIG.  37. — MAP  OF  STREAMS  THAT  FLOW  FROM 
MOUNTAINS  TOWARD  A  LARGE  LAKE,  BUT 
DRY  UP  BEFORE  THEY  REACH  IT. 


88 


A   READER   IN   PHYSICAL   GEOGRAPHY. 


they  able  to  continue  on  their  way  would  undoubtedly 
reach  their  goal.  (See  Fig.  37.) 

We  may  describe  a  river,  then,  as  a  stream  of  water 
and  detritus,  flowing  toward  the  ocean.  This  definition 
tells  the  whole  truth,  and  allows  all  rivers  to  be  grouped 
together,  without  giving  any  false  ideas. 

The  Deposits  of  Running  Water.  Alluvial  Plains. 
- — The  materials  thus  dropped  by  a  stream  when  it  finds 


FIG.    38. — A  VERMONT    STREAM   THAT   IS  UNDERCUTTING   ITS   BANK.      CON- 
TRAST    SLOPES    ON    OPPOSITE    SIDES    OF    STREAM. 

itself  overloaded  are  left  in  very  definite  forms.  At  first 
the  winding  river  drops  some  of  its  load  on  the  inside  as 
it  turns  a  corner,  and  rushing  more  swiftly  on  the  out- 
side cuts  a  deeper  channel,  and  perhaps  undercuts  the 
sides  of  the  channel,  leaving  a  steep  bank.  (See  Figs. 
38  and  39.)  The  country  boy  living  near  a  stream  knows 
the  deep  part  of  the  stream  as  his  swimming  pool,  the 
sandy  or  gravelly  slope  on  the  inside  of  the  curve  as  his 
out-of-door  bath-house,  and  the  steep  bank,  perhaps,  as 
a  diving  board. 


THE   DEPOSITS   OF   RUNNING  WATER.  89 

Gradually,  by  this  process  of  dropping  the  larger  parti- 
cles of  its  load,  the  river  succeeds  in  building  up  a  large 
flat  plain  along  the  sides  of  its  course  between  the  steeper 
walls  of  the  side  and  the  channel.  This  plain,  being  made 
of  more  or  less  fine  material,  is  usually  good  farm  land, 
and  in  narrow,  deep  valleys  is  the  place  where  railroads 
and  roads  are  built.  Such  flat  plains  of  greater  or  less 


FIG.    39. — A   DRY  STREAM   BED,  SHOWING  CURVES  AND  SLOPES   OF    STREAM. 
NOTICE   ALSO   IRRIGATION    DITCH    ON   THE    SIDE   OF   THE    RIDGE. 

size  along  most  rivers  are  known  as  alluvial  plains,  and 
may  be  seen  in  miniature  in  the  wayside  mud  puddle. 
(See  Fig.  40.) 

Some  of  the  great  alluvial  plains  of  our  greater  rivers 
form  the  richest  farming  land  that  can  be  desired.  The 
alluvial  plain  of  the  Mississippi,  that  extends  from  the 
mouth  of  the  Ohio  River  to  the  Gulf  of  Mexico,  and 
through  which  the  great  river  wanders,  or  meanders,  in 
a  very  crooked  course,  is  a  wonderfully  rich  farming 
region,  devoted  largely,  at  least  in  its  more  southerly  part, 


90  A   READER   IN   PHYSICAL   GEOGRAPHY. 

to  cotton  and  sugar-cane.  (See  Fig.  9.)  Such  alluvial 
plains  are  not,  however,  perfectly  flat,  and  do  not,  as  a 
rule,  slope  from  the  sides  of  the  valley  to  the  stream,  but 
from  the  stream  toward  the  sides  of  the  valley.  Thus 
the  parts  of  the  plain  back  from  the  stream  are  often  not 
so  high  as  the  banks  of  the  river,  especially  when  the 
banks  have  been  made  higher  by  the  building  of  levees, 
as  along  the  lower  course  of  the  Mississippi.  Hence 


FIG.  40. — AN  ALLUVIAL  PLAIN  IN  IRELAND.      NOTE   THE   CROOKED  COURSE 
OF   THE    STREAM    AND    THE    WALL    MARKING    THE    HAY    FIELD. 


these  regions  are  -often 


more  or  less  swampy,  and  are 
subject  to  overflow  when  the  river  is  in  flood.  It  is  the 
lower  portions  of  the  alluvial  plain  of  the  Mississippi  that 
are  often  covered  to  great  depths  in  freshets,  causing  a 
large  loss  of  life  and  property.  On  the  Donaldsonville 
sheet  of  the  United  States  Geological  Survey  map  of 
Louisiana  the  houses  are  all  shown  as  being  close  to  the 
river,  and  the  swampy  area  away  from  the  river  is  crossed 
by  streams  that  start  within  less  than  a  quarter  of  a  mile 


THE   DEPOSITS  OF   RUNNING  WATER.  9! 

of  the  Mississippi,  and  flow  away  from  it.  (See  Fig.  41.) 
The  great  Yazoo  River  follows  such  a  course  in  a  marked 
way,  flowing  in  the  lower  depression  between  the  Missis- 
sippi River  and  the  bluffs  bounding  the  alluvial  plain  to 
the  east,  until  finally  the  Mississippi  River,  swinging  to 


1  2  3 

FIG.  41. — MAP  OF  MISSISSIPPI  R^VER  AND  PLAIN  AT  DONALDSONVILLE, 
LOUISIANA.  NOTE  SMALL  STREAMS  FLOWING  AWAY  FROM  MAIN 
RIVER  ;  ALSO  PATHS  OF  CANALS  AND  POSITION  OF  HOUSES. 

the  east  and  striking  against  the  bluff,  gives  the  Yazoo 
River  a  chance  to  enter  the  main  stream.  Close  to  this 
point,  where  the  river  comes  against  the  bluff,  is  the  city 
of  Vicksburg,  Mississippi,  on  the  bluff.  Natchez,  Missis- 
sippi, and  Memphis,  Tennessee,  are  other  illustrations 
of  large  cities  safely  placed  on  bluffs,  but  close  to  the 


92  A   READER  IN  PHYSICAL  GEOGRAPHY. 

Mississippi  River  and  to  the  rich  land  of  its  alluvial 
plain.  Such  a  position  is  the  wisest  and  safest,  and 
hence  is  very  frequently  chosen.  As  large  towns  in  great 
alluvial  plains  are  exceptions,  we  may  say  that  the  bluff 
location  is  the  rule. 

Alluvial  Fans. — Such  river-made  plains  as  have  been 
described  are  the  characteristic  forms  in  which  overloaded 
rivers  lay  down  their  extra  burden  as  the  decreasing  down- 
stream slope  causes  their  ability  to  carry  the  load  to 
weaken.  The  forms  in  which  the  load  is  deposited  when 
a  river  course  changes  suddenly  from  a  steep  slope  to  a 
gentle  slope,  or  when  a  river  runs  into  a  standing  body 
'of  water,  are  no  less  important,  and  in  some  cases  more 
interesting.  In  the  first  place,  since  the  slope  changes 
abruptly,  the  power  of  the  stream  to  do  its  work  is  sud- 
denly decreased ;  it  cannot  stop  to  drop  its  load  a  little  at 
a  time,  but  must  drop  most  of  it  at  once.  Such  sudden 
changes  of  slope  occur  usually  where  tributary  streams 
from  a  side  valley  with  steep  slopes  run  into  the  more 
gently  flowing  main  or  master  stream ;  or  where  short, 
swift  streams  from  mountains  run  across  plains  or  through 
lowlands  on  their  way  to  the  sea.  Under  such  condi- 
tions we  often  find  deposits  known  as  fans,  which  are 
really  great  conical  heaps  of  material,  with  the  point  of 
the  cone  in  the  mouth  of  the- depositing  tributary  river 
and  the  base  of  the  cone  creeping  out  over  the  adjacent 
lowland.  The  form  is  such  as  would  be  made  by  open- 
ing a  fan  out  flat,  and  then  curving  it  by  pressing  up 
under  the  middle  sticks  and  down  along  the  outer  sticks. 
(See  Figs.  42  and  70.)  Fans  of  small  size  may  be  seen 
in  almost  any  ploughed  field  or  sand-bank  after  a  heavy 
rain.  Were  the  material  dumped  by  the  river  in  open 
country,  and  not  piled  up  on  the  side  of  the  valley,  the 


ALLUVIAL    FANS.  93 

detritus  would  accumulate  in  a  perfect  cone,  such  as  one 
can  sometimes  see  in  coal  yards  where  the  coal  is  dumped 
in  the  centre  of  an  open  space  from  an  elevator,  or  in 
the  piles  of  sand  beneath  the  screen  where  masons  are 
screening  sand  for  mortar. 

In  such  cases  it  is  seen  that  much  of  the  material  poured 
on  the  top  usually  runs  to  the  very  bottom  of  the  slope, 
thus  building  the  cone  forward  as  it  grows  upward.  In 
a  similar  way  in  the  river-made  half-cones  or  fans,  the  fan 


FIG.    42. — PROFILE    OF    A    LARGE    ALLUVIAL   FAN    IN   UTAH.       THE   DEPOSIT- 
ING   RIVER    FLOWS    FROM    RIGHT   TO    LEFT. 

builds  forward  as  it  grows  upward.  Above  are  the  sharp- 
sided,  narrow  ravines  made  by  the  swift-running  water, 
and  at  the  foot  of  the  steep  slope  are  the  many  fans  of 
various  sizes  and  slopes,  coarse  materials  building  up 
steep  fans,  and  fine  materials  more  gently  sloping  fans. 
Sometimes  the  fans  are  so  numerous  along  the  face  of  a 
steep  cliff  or  bluff  that  they  finally  meet,  thus  forming  a 
continuous  slope  of  detritus,  like  a  talus  with  a  gentle 
slope. 

Alluvial  fans  are  important  and  interesting  for  other 
reasons  than  because  of  their  shape  and  origin.     They 


94  A   READER   IN   PHYSICAL   GEOGRAPHY. 

are  often  topographic  forms  of  great  use  to  man,  the 
great  fan  of  the  Hwang-ho  in  China,  one  of  the  largest 
known,  being  one  of  the  most  densely  populated  regions 
on  the  globe.  This  example  is  noteworthy  also,  because 
it  occasionally  illustrates  the  fact  that  rivers  crossing  fans 
may  flow  down  the  slope  in  any  direction  with  almost 
equal  ease.  If  a  river  flowing  on  a  fan  changes  its  course 
suddenly,  as  the  Hwang-ho  has  a  way  of  doing  from  time 
to  time,  destruction  must  follow.  We  can  often  illus- 
trate this  process  in  a  wayside 'stream  by  putting  a  pebble 
or  a  handful  of  earth  in  the  channel  occupied  by  the 
stream,  thus  changing  its  course  at  once.  In  many  cases 
in  mountainous  regions,  as  the  Alps,  the  fans  are  the 
most  fertile  land,  and  are  the  seats  of  the  villages  and  the 
best  fields.  Occasionally  small  fans,  being  made  of  mate- 
rials a  little  coarser  in  character  than  the  adjacent  low- 
lands, are  occupied  by  the  houses  and  farm  buildings, 
while  the  better  land  of  the  lowlands  is  given  over  to 
cultivation.  Examples  might  also  be  given  where  allu- 
vial fans  form  naturally  graded  roads  up  into  steep-sided 
valleys,  which  are  used  as  highways.  Thus  their  uses  are 
many  and  their  importance  great.  They  might  be  called 
open-air  deltas,  as  their  form  is  similar  to  those  deposits 
which  we  call  deltas,  made  where  rivers  run  into  standing 
bodies  of  water,  such  as  a  lake  or  the  ocean. 

Deltas. — If  we  watch  a  small  stream  running  down  a 
hillside  in  a  rainstorm,  and  flowing  into  a  small  mud 
puddle,  we  shall  see  that  the  water  is  thick  and  yellow 
with  the  load  it  is  carrying.  After  the  rain  has  ceased, 
and  the  mud  puddle  dried  up,  we  shall  find  in  the  bot- 
tom of  the  little  hollow  a  flat-topped  pile  of  sand  and 
mud  extending  from  the  shore  into  the  deeper  part  of 
the  puddle.  Such  a  delta  shows  us  in  miniature  the 


DELTAS.  95 

more  important  features  of  the  famous  large  deltas  of 
such  rivers  as  the  Mississippi  and  the  Nile.  If  we  look 
carefully  at  the  front  of  the  delta,  we  shall  find  it  irregu- 
lar and  somewhat  scalloped  in  outline,  bounded  by  a 
somewhat  steep  slope,  and  curving  forward  into  the 
puddle  wherever  a  small  branch  of  the  main  stream  has 
brought  down  and  dumped  an  accumulation  of  materials. 
Perhaps  we  may  be  able  to  see  the  small  channels  run- 
ning across  the  delta  and  branching  from  the  former 
mouth  of  the  main  stream  as  the  ribs  of  an  oak  or  maple 
leaf  branch  from  the  main  stem.  Such  channels,  com- 
mon to  deltas  as  they  are  to  alluvial  fans,  show  us  that 
the  main  stream  is  divided  at  the  head  of  the  delta  into  a 
number. of  branches,  each  doing  the  same  kind  of  work, 
and  each  depositing  its  share  of  load  at  the  front  of  the 
delta. 

Streams  running  toward  the  main  or  master  stream  in 
the  river  valley  have  been  called  tributaries^  because  they 
contribute  water  and  detritus  to  the  main  trunk  stream. 
In  the  same  way,  streams  flowing  away  from  the  master 
stream,  as  they  do  in  deltas,  and  distributing  the  load 
and  the  water  in  several  different  directions,  may  be 
called  distributaries.  If  we  look  at  a  whole  river  system, 
we  shall  find  that  the  tributaries  run  toward  one  another 
and  join  the  main  trunk,  as  the  leaves  of  a  corn-stalk  join 
the  main  stalk;  the  distributaries  run  away  from  the 
main  trunk,  as  the  roots  of  the  corn  branch  from  the 
main  stalk.  In  the  corn-stalk  much  of  the  water  received 
is  carried  down  and  distributed  around  the  roots;  a  simi- 
lar distribution  occurs  in  the  case  of  a  river. 

When  deltas  grow  up  to  the  surface  of  the  water,  they 
of  course  become  land,  and  their  rivers  continue  across 
them  to  their  outer  edge,  thus  changing  the  shape  of  the 


96 


A   READER  IN   PHYSICAL  GEOGRAPHY. 


shore  line  and  extending  the  river  valleys.  (See  Fig.  43.) 
This  land  usually  being  formed  of  fine  soil,  such  as  is  found 
in  the  alluvial  plain,  is  naturally  very  rich,  and,  like  the 
alluvial  plain,  may  thus  be  of  very 
great  importance  in  agriculture.  This 
is  particularly  well  illustrated  in  the 
delta  of  the  Nile,  which  is  famous  for 
its  abundant  crops  of  rice  and  sugar- 
cane. Sometimes,  however,  the 
growth  of  a  delta  at  the  mouth  of 
a  stream,  particularly  of  a  large  stream 
like  the  Mississippi,  is  embarrassing, 
because  no  one  of  the  distributing 
branches  keeps'  its  channel  deep 
enough  to  allow  the  entrance  of 
large  vessels.  In  such  cases  com- 
merce can  be  carried  on  only  after 
the  channel  has  been  deepened  at 
great  expense  and  with  great  effort. 
This  has  been  done  in  the  case  of 
the  Mississippi,  so  that  now  ocean 
vessels  go  up  the  river  over  one 

.,  XT  ^    i 

hundred  miles  to  New  Orleans. 

Rapids  and  Waterfalls.  —  We  have 
MENT  OF  DISTRIBU-     spoken  thus  far  as  though  a  stream 

TARIES,    NUMBER    OF         flowed     from     SQurce     to     moUth    with- 
MOUTHS,  AND    RELA-  .  .  ,11 

TION  OF  COMMERCE     out  any  interruption,  and  as  though 

TO  RIVER.  it  might  cut  down  its  channel  toward 

the  level   of   the  sea  without   being 

hindered  in  its  work  by  any  features  of  the  earth  itself. 

Such  is  not  the  case,  however;  for  if  we  follow  down  any 

small  stream,  and  many  large  ones,  we  find  that  the  rate 

of  flow  is  sometimes  rapid  and  sometimes  slow.     For 


FIG.  43.  —  MAP  OF  MIS- 
SISSIPPI  DELTA, 
NOTE  THE  ARRANGE- 


RAPIDS  AND   WATERFALLS.  9? 

instance,  if  we  should  study  the  Bronx  River  as  it  flows 
through  Bronx  Park  in  New  York  City,  we  should  find 
in  the  upper  course  a  slow,  sluggish,  crooked  stream, 
flowing  through  a  small  alluvial  plain ;  at  the  lower  end 
of  the  alluvial  plain  we  suddenly  enter  a  deep,  rocky 
gorge,  through  which  the  river  flows  rapidly  and  in  a 
rather  straight  course.  The  rapids  are  formed  in.  this 
river,  as  in  all  rivers,  wherever  there  is  any  barrier  that 
prevents  the  river  from  wearing  there  as  rapidly  as  it  can 
up  or  down  stream.  Such  a  barrier  is  very  frequently  a 
layer  of  strong  rock  that  crosses  the  stream,  and  through 
which  the  river  must  saw  its  way.  As  the  running  water 
must  flow  down  hill  to  reach  the*  sea,  no  part  of  the 
course  up  stream  can  be  worn  lower  than  the  edge  of  the 
down-stream  barrier  that  causes  the  rapid  or  fall.  As  the 
barrier  is  cut  down,  however,  the  up-stream  valley  can 
be  lowered  to  correspond  with  this  lower  level.  For 
instance,  the  valley  up  stream  from  Niagara  Falls  cannot 
be  worn  down  any  lower  than  the  falls,  for  water  must 
have  a  slope  to  run  on.  Niagara  is,  however,  being 
slowly  worn  down,  and  just  as  slowly  Lake  Erie  is  being 
drained  of  its  water. 

Sometimes  above  the  barrier  we  find  a  lake,  some- 
times an  alluvial  plain,  or  a  flat  valley  that  may  be  used 
for  agricultural  purposes.  In  any  case,  the  stream  may 
be  divided  into  what  may  be  called,  in  the  language  of  the 
camper  and  canoer,  rapids  and  reaches.  In  the  reaches 
canoeing  may  be  possible,  as  the  current  is  slow;  where 
there  is  a  rapid  or  a  fall,  canoeing  is  usually  impos- 
sible, and  the  traveller  must  carry  his  boat  and  his  equip- 
ment around  the  obstruction.  Hence  at  such  places  we 
have  a  so-called  portage,  or  a  carry. 

Rapids  indicate  the  place  where  usually  the  water  may 
7 


98  A   READER  IN   PHYSICAL  GEOGRAPHY. 

be  made  to  accumulate  by  building  a  dam,  in  order  that 
a  supply  may  be  secured  which  will  be  available  in 
dry  times  as  well  as  immediately  after  rains.  If  we  ex- 
amine the  location  of  the  large  manufacturing  towns  of 
New  England,  we  shall  find  a  great  many  of  them  located 
at  or  near  the  fall  of  some  large  river,  which  gave  them 
water  for  power  and  made  their  growth  possible.  Where 
the  stream  is  large  and  clear,  and  the  fall  high,  we  may 
have  an  object  of  scenic  interest  famous  for  its  beauty. 
For  instance,  at  Niagara  Falls  the  water  leaps  over  a 
precipice  160  feet  high,  making  a  wonderful  spectacle 
known  the  world  over. 

Results  of  Work  of  Running  Water. — If  the  processes 
of  atmospheric  and  river  erosion  continue  for  any  great 
length  of  time,  there  must,  of  course,  be  a  great  change, 
not  only  in  the  shape  of  the  land  surface,  but  in  its 
height  above  the  level  of  the  sea.  We  cannot  contin- 
ually remove  materials  from  a  place  without  lessening 
the  quantity  there.  Hence  the  lands  of  the  world  must 
be  gradually  lowering,  and  the  highlands  must  be  grow- 
ing less  high,  under  the  attacks  of  the  forces  we  have 
considered.  Or,  as  we  may  say,  the  lands  grow  old, 
become  worn  down  more  nearly  to  the  level  of  the  sea, 
being  then  less  rugged,  with  large  streams  flowing  slowly 
and  smoothly  through  them. 

As  the  river  is  the  main  route  whereby  the  detritus  of 
the  land  can  be  carried  to  its  goal  in  the  sea,  it  is  impos- 
sible for  the  lands  to  be  worn  down  perfectly  flat ;  there 
must  always  be  a  gentle  down-hill  slope,  so  that  the 
water  will  run  off.  As  time  goes  on,  however,  the  peaks 
and  divides  between  adjacent  streams  become  less  and 
less  sharp,  and  the  slopes  more  and  more  gentle.  It 
should  be  noted,  however,  that  when  the  land  is  low 


RESULTS   OF  WORK   OF   RUNNING  WATER.  99 

there,  is  no  more  land  draining  its  water  to  the  sea  than 
there  was  when  the  land  was  high;  it  may,  however,  be 
drained  much  more  quickly  after  a  rain,  owing  to  the 
removal  of  the  barriers  of  the  lakes  which  formerly  held 
the  water  back. 


CHAPTER   X. 
THE   WORK   OF   STANDING  WATER. 

Kinds  of  Standing  Water. — We  have  already  sug- 
gested that  a  large  part  of  the  water  of  the  world  stands 
more  or  less  quietly  in  lakes  or  in  the  ocean,  and  in  the 
associated  seas,  bays,  and  gulfs.  Were  it  not  for  the 
forces  that  set  the  surface  of  the  water  in  motion,  stand- 
ing water  would  be  of  little  importance  as  an  agent  of 
erosion,  for  it  would  lack  power  of  delivering  blows  on 
the  land.  Any  of  us  who  are  familiar  with  the  beach, 
however,  know  that  standing  water  is  rarely  quiet,  ex- 
cept, perhaps,  in  a  summer  calm ;  motion  of  some  sort 
being  almost  continuous,  the  work  accomplished  must  be 
important.  Standing  water  may  be  in  motion  in  any  one 
of  three  ways,  as  surface  waves,  as  continuous  currents, 
or  as  intermittent  tides.  If  we  blow  steadily  on  a  small 
pan  of  water  we  set  its  surface  in  ripples,  which  will 
swash  against  the  side  of  the  pan,  and  rise  and  fall  as  do 
waves;  if  we  blow  constantly  at  one  spot,  we  shall  finally 
set  a  large  part  of  the  water  in  motion  around  the  pan, 
or  we  shall  start  currents.  Tides  cannot  be  so  easily 
illustrated  by  experiment. 

Each  of  these  three  motions  can  do  work,  but  as  that 
work  is  mostly  confined  to  the  surface  of  the  water,  it  is 
the  coast  rather  than  the  bottom  of  the  sea  or  lake  that  is 
eroded.  As  the  water  stands  at  a  nearly  constant  level, 
the  marks  made  by  the  water  work  must  be  nearly  at  the 
same  height,  so  that  water  cuts  horizontally  rather  than 


WAVE   EROSION.  IOI 

vertically.  Here  is  the  great  distinction  between  the 
work  of  standing  water  and  running  water.  Running 
water  makes  a  country  rough,  with  more  or  less  steep 
and  irregular  slopes;  standing  water  tends  to  cut  great 
horizontal  benches  in  the  land,  with  bluffs  above,  giving 
a  very  regular  form  of  topography,  made  up  of  few  slopes. 
Let  us  study  these  three  forms  of  motion,  and  see  the 
results  of  their  work. 

Wave  Erosion. — The  most  conspicuous  and  important 
of  these  three  forms  of  work  is  that  done  by  the  waves. 
We  are,  perhaps,  familiar  with  the  small  waves  raised  on 
the  leeward  side  of  a  river,  which  continually  slap  up 
against  the  land  with  a  little  swish,  perhaps  rolling  a  few 
pebbles  on  the  shore  back  and  forth ;  we  see  the  water 
roll  in,  we  see  it  fall  or  break,  and  then  comes  the  sheet 
of  water  made  by  the  falling  wave,  which  runs  up  the 
shore,  if  the  shore  be  gentle,  for  a  considerable  distance. 
The  little  pebbles  are  rattled  together,  and  are  borne  first 
up  the  shore,  and  then  down,  as  the  waves  run  in  and 
out.  If  we  go  to  the  ocean  in  a  time  of  storm,  and 
particularly  to  a  sandy  shore,  we  shall  see  the  same  pro- 
cess, only  on  a  larger  scale.  (See  Fig.  44.)  The  waves 
will  roll  in  in  great  size,  nine  or  ten  times  a  minute,  and 
will  thunder  down  on  the  shore,  and  rise  up  perhaps  in 
spray.  We  may  be  able  to  feel  the  jar  of  the  waves  as 
they  fall,  and  appreciate  the  fact  that  the'  earth  has  been 
dealt  a  great  blow  that  has  made  it  quiver.  As  the  wave 
slides  up  the  beach  toward  our  feet  in  a  thin  sheet  of 
foaming  water,  we  may  hear  the  crackle  of  the  little 
pebbles  as  they  are  rattled  together;  as  the  wave  runs 
back  to  meet  the  next,  we  can  see  the  pebbles  running 
down  the  shore,  and  can  hear  the  fainter  crackle,  and  see 
that  the  water  is  muddy  with  the  material  it  is  carrying. 


IO2 


A   READER  IN   PHYSICAL  GEOGRAPHY. 


The  finer  mud  will  probably  be  carried  slowly  out  into 
deep  water,  and  there  quietly  deposited. 

Thus  in  the  falling  and  advancing  wave  there  is  the 
same  work  of  erosion,  the  same  carrying  of  a  load,  the  same 
preparation  of  material  for  final  deposition  in  the  sea, 
that  we  saw  in  the  case  of  running  water.  If  we  exam- 


FIG.  44. — BREAKING  WAVES  ON  A  NEW  JERSEY  COAST.  NOTE  THE 
BREAKING  WAVE,  AND  THE  SHEET  OF  WATER  FORMED  FROM  PRE- 
CEDING WAVE. 

ine  one  of  the  pebbles  we  shall  find  it  well  rounded,  with 
every  mark  of  having  been  recently  shaped.  Its  surface 
will  not  be  at  all  weathered.  This  is  the  natural  process 
of  rock-rounding  which  is  utilized  in  the  making  of  mar- 
bles, where  the  regular  blocks  of  material  are  turned  in 
a  rotating  cylinder,  until  finally  they  have  had  all  their 
corners  knocked  off. 

In  some  cases  we  can  experience  the  active  pull  of  the 


WAVE   EROSION.  IO3 

waves  in  carrying  materials  toward  the  sea,  by  standing 
in  shallow  water,  and  allowing  the  waves  to  run  in  and 
out  around  our  feet.  We  may  feel  a  strong  rush  of  the 
water  close  to  the  ocean  bottom,  and  realize  that  the 
materials  are  being  carried  away  from  around  our  feet,  so 
that  it  seems  as  if  we  should  be  undermined.  This  pull 
of  the  waters  as  the  wave  runs  back  to  the  ocean  is  known 


FIG.    45.— SEA   CAVES   AT   LA  JOLLA,    CALIFORNIA. 

as  the  undertow,  and  is  a  very  important  part  of  the  wave 
work,  for  the  detritus  worn  from  the  land  is  carried  to  its 
long  resting-place  in  the  sea  largely  by  this  process. 

The  place  to  see  the  waves  at  work  with  their  greatest 
force  is  perhaps  on  a  rocky  shore,  where  they  thunder  in 
against  the  base  of  a  great  cliff,  slowly  sawing  horizon- 
tally into  the  rock  mass.  In  such  a  case,  as  along  many 
parts  of  the  coast  of  Maine  and  California,  we  find  at  the 


104  A   READER  IN  PHYSICAL  GEOGRAPHY. 

foot  of  the  cliff,  and  at  the  level  of  high  tide,  a  little  cave 
cut  into  the  cliff  itself.  (See  Fig.  45.)  The  cave  may  be 
exposed  and  left  dry  when  the  tide  is  out.  From  their 
likeness  and  shape  to  the  old-fashioned  tin  or  Dutch 
oven,  that  was  placed  in  front  of  a  wood  fire  with  the 
open  side  toward  the  fire,  such  caves  are  known  in 
Maine  as  ovens.  When  the  cave  has  been  cut  back  so 
that  the  overlying  rock  is  no  longer  supported  by  the 
under  rock,  it  falls  into  the  sea,  thus  feeding  the  waves 
with  new  materials  to  be  worn  out  and  carried  away. 

Usually  on  a  rocky  shore  all  parts  of  the  land  are  not 
of  equal  strength.  Then  naturally  the  waves  cut  more 
actively  and  effectively  on  the  weaker  parts,  cutting  them 
back  as  bays,  and  allowing  the  strong  portions  to  remain 
projecting  into  the  sea  as  headlands  that  receive  the 
blows  of  the  water  with  the  least  damage.  (See  Fig.  46.) 
Thus  we  have  an  irregular  shore  line  made,  with  possibly 
deep  bays  that  make  good  harbors.  The  headlands  being 
high,  and  projecting  into  the  sea,  are  dangerous  to  navi- 
gation, so  that  sailors  must  be  warned  of  their  presence. 
Hence  we  expect  lighthouses  of  high  power  to  be  placed 
at  such  spots  on  the  shore,  as  we  see  on  the  Island  of 
Grand  Manan.  They  warn  the  passing  mariner  to  keep 
away  from  shore,  and  when  near  a  harbor  show  the 
entrance  into  it,  as  in  the  case  of  the  Navesink  Lights  at 
the  entrance  to  New  York  Harbor.  Dangerous,  rocky 
shoals  made  by  the  incomplete  cutting  down  of  a  head- 
land are  also  marked  by  such  a  beacon,  as  at  Minot's 
Ledge  in  Boston  Harbor,  or  at  Eddystone  Rocks  in 
the  English  Channel. 

Sometimes  the  weaker  rocks  are  worn  back  by  the 
waves,  and  long,  deep  chasms  are  formed,  into  which  the 
water  rushes  with  tremendous  force  and  with  great  noise. 


WAVE   DEPOSITS. 


105 


Occasionally  part  of  the  roof  of  such  a  chasm  falls  in, 
making  a  hole  through  which  the  water  may  be  spouted 
at  high  tide,  giving  us  a  so-called  spouting  horn,  of  which 
there  are  excellent  examples  at  Newport,  Rhode  Island, 
and  Marblehead  Neck,  Massachusetts. 

Wave   Deposits. — The   materials   removed    from   the 


FIG.    46. — A   HEADLAND    IN    ENGLAND,    WITH   A    SEA    CAVE    IN   PROCESS   OF 

FORMATION. 

land,  and  particularly  from  the  headlands,  are  carried 
along  shore,  and  in  part  deposited  in  the  bays  in  what 
are  known  as  beaches.  Sometimes  the  headlands  are  so 
near  together  that  the  beaches  are  like  little  pockets  in 
which  the  sand  and  gravels  accumulate,  and  are  then 
known  as  pocket  beaches.  (See  Fig.  47.)  If  we  pass 
from  the  headlands  toward  the  centre  of  such  a  beach,  we 
shall  usually  find  the  pebbles  growing  finer  and  finer,  as 


106  A   READER   IN   PHYSICAL   GEOGRAPHY. 

we  get  farther  from  the  sources  of  supply.  If  the  head- 
land on  one  side  of  the  beach  is  made  of  one  kind  of  rock, 
and  that  on  the  other  of  another,  we  may  find  most  of  the 
materials  of  the  beach  like  the  nearest  headland. 

Where  the  land  is  of  uniform  strength,  the  waves 
have  little  opportunity  of  carving  it  into  headlands  and 
bays  and  we  are  apt  to  find  long,  straight  sand-beaches, 


FIG.  47. — A   POCKET   BEACH    IN  MAINE,  USED   AS  A  FISHERMAN'S   LANDING. 

such  as  those  along  the  New  Jersey  and  Long  Island 
'shores,  which  extend  for  miles  with  few  interruptions. 
They  are  made  of  the  materials  brought  in  part  from 
the  land,  and  in  part  from  the  bottom  of  the  sea  as  the 
waves  have  rolled  them  in.  Sometimes  we  find  such 
long  beaches  formed  quite  a  distance  offshore,  and  not 
connected  with  the  mainland  except  at  one  end.  Such 
beaches  were  once  offshore  bars,  formed  where  the  waves 
first  broke.  Finally  they  grew  above  the  level  of  the  sea. 


WAVE   DEPOSITS. 


107 


In  such  a  case 
there  exists  between 
the  offshore  beach 
and  the  coast  line  a 
lagoon  of  more  or 
less  quiet  water, 
with  an  outlet  to 
the  sea,  such  as  we 
have  on  the  south 
side  of  Long  Island, 
in  Great  South  Bay, 
inside  of  the  barrier 
beach  known  as  Fire 
Island  Beach,  and  at 
Sandy  Hook,  New 
Jersey.  (See  Fig. 
48.)  The  waters  of 
the  bay  are  shallow 
and  usually  quiet, 
and  form  excellent 
yachting  grounds, 
and  fishing  grounds 
for  oysters  and 
clams.  The  barrier 
beach,  as  in  the  case 
of  most  of  the 
beaches  of  New 
Jersey,  being,  as  it 
were,  out  in  the 
sea,  is  an  excellent 
place  for  a  summer 
resort,  as  there  will 
be  a  water  breeze, 


LIFE  SAVING  STATIONS X        A---Lr'HT  HOUSES 

SCAIE  OF  MILES  minimum         RAILROADS 


S^£jfc^'^y«  *•««»*  ««• 

/•\  ^/-^ 


FIG.  48. — MAP  OF  SANDY  HOOK,  NEW  JERSEY, 
SHOWING  A  BARRIER  BEACH  ENDING  IN  A 
HOOKED  SPIT.  NOTE  HOW  HARBOR  IS 
FORMED,  AND  POSITION  OF  LIGHTHOUSES 
AND  LIFE-SAVING  STATIONS. 


108  A   READER   IN   PHYSICAL  GEOGRAPHY-. 

no  matter  from  what  direction  the  wind  blows.  Such 
sandy,  regular  beaches  have  but  few  large  indentations 
suitable  for  harbors,  as  we  can  see  by  studying  the  coast 
line  of  New  Jersey  from  New  York  southward.  Hence 
they  cannot  be  the  seat  of  many  large  commercial  centres. 

Harbors  will  occur  wherever,  through  a  sinking  of  the 
land,  the  salt  water  has  been  allowed  to  enter  the  sub- 
merged or  drowned  river  valley,  forming  a  good  estuary, 
as  in  the  case  of  the  Hudson  River  and  Delaware  Bay. 
Any  sandy  beach  near  a  large  city,  such  as  Coney  Island, 
is  a  good  place  for  a  summer  centre  of  life,  though  the 
winds  blow  from  the  sea  but  a  part  of  the  time. 

Small,  short  beaches  are  also  frequently  formed  be- 
tween an  island  and  the  mainland,  where  the  waves,  roll- 
ing in  together  from  opposite  sides  of  the  island,  meet 
and  lose  their  carrying  power.  If  such  a  beach  grows  to 
the  surface  of  the  water,  the  island  will  be  tied  to  the 
mainland  or  to  another  island,  and  we  may  have  an  isth- 
mus and  a  peninsula;  if  the  beach  be  removed,  the  penin- 
sula will  again  be  changed  into  an  island.  Such  island 
tying  and  untying  is  a  common  result  of  ocean  work. 

Ocean  Currents. — The  second  way  in  which  standing 
water  is  set  in  motion  is  in  the  form  of  ocean  currents, 
as  we  have  already  noted.  At  the  centre  of  the  great 
oceans,  as,  for  instance,  in  the  North  Atlantic,  the  water 
is  practically  quiet,  and  often  so  filled  with  plant  life  that 
navigation  is  somewhat  difficult,  as  was  discovered  by 
Columbus  in  his  first  voyage.  About  such  a  quiet  centre 
there  is  a  very  systematic  circling  of  the  waters  in  a  slow 
and  steady  course.  If  one  should  stand  in  the  centre  of 
either  northern  ocean,  the  waters  of  the  edges  of  the 
ocean  would  be  drifting  about  him  as  the  hands  of  a  clock 
or  watch  move  about  the  centre,  from  left  to  right ;  if  one 


OCEAN   CURRENTS.  109 

should  stand  in  a  similar  position  in  the  centre  of  either 
of  the  great  southern  oceans,  the  water  would  drift  about 
him  in  the  opposite  direction,  from  right  to  left. 

Such  ocean  currents  are  very  frequently  spoken  of  as 
streams;  but  the  word  stream  is  more  truthfully  applied 
to  a  narrow  and  special  current  of  water  flowing  with 
considerable  force  through  slower  moving  water  on  either 
side,  as  the  Gulf  Stream,  which  flows  at  a  rate  of  80  or 
90  miles  a  day  out  from  the  Gulf  of  Mexico,  and  north- 
eastward across  the  North  Atlantic.  This  stream  is, 
however,  but  a  small  part  of  the  great  system  of  moving 
waters  of  the  North  Atlantic,  which  may  very  well  be  called 
the  North  Atlantic  Drift,  the  word  drift  suggesting  very 
well  the  easy-going  rate  at  which  the  water  progresses. 

As  the  currents  move  generally  from  warm  regions 
to  cold  on  the  western  sides  of  the  oceans,  and  from 
cold  regions  to  warm  on  the  eastern  sides,  the  ocean 
waters  in  most  regions  are  colder  or  warmer  than  the 
average  temperatures  of  the  adjoining  lands.  As  the 
winds  move  over  the  oceans  the  air  becomes  warmed 
or  chilled  by  the  water  beneath.  When  the  winds  blow 
from  a  warm  ocean  to  a  cool  land,  as  in  the  winter  they 
blow  from  the  North  Atlantic  upon  the  shores  of  Europe, 
the  lands  they  reach  become  warmer  than  other  lands 
in  the  same  latitude.  In  the  same  way  winds  blowing 
over  cool  currents  become  chilled  and  carry  low  tem- 
peratures with  them.  It  is  not,  therefore,  the  drifting  of 
ocean  currents  upon  a  shore  that  changes  the  tempera- 
ture of  the  land,  but  the  drifting  of  wind  that  has  been 
warmed  or  cooled  by  blowing  over  the  currents.  It  is 
because  of  this  effect  of  the  currents  upon  the  accom- 
panying winds,  that  the  continents  on  the  eastern  side 
of  an  ocean  may  be  occupied  to  much  higher  latitudes 


1 10  A   READER   IN   PHYSICAL   GEOGRAPHY. 

than  on  the  western,  as  is  seen  by  comparing  the  posi- 
tion of  the  great  English  nation  on  the  British  Isles,  on 
the  eastern  side  of  the  North  Atlantic,  with  the  desolate 
and  uninhabited  coast  of  Labrador,  at  the  same  distance 
from  the  equator  on  the  western  side  of  the  same  ocean. 

There  are  many  smaller  and  subordinate  ocean  currents 
besides  the  systematic  drifts  mentioned  ;  but  their  effects 
are  not  very  important,  though  perhaps  mention  should 
be  made  of  the  cold  Labrador  current  that  chills  the 
northeastern  United  States,  as  it  creeps  down  along 
the  Labrador  and  Maine  coasts  until  it  meets  with 
and  disappears  beneath  the  warmer  waters  of  the  Gulf 
Stream.  Along  the  border  where  these  currents  first 
come  together  we  have  the  famous  fog  banks  of  New- 
foundland. (See  Fig.  49.) 

The  ocean  currents,  running  largely  along  shore,  do 
but  little  work  in  wearing  away  the  continent,  as  their 
force  cannot  be  applied  directly  to  the  continent,  as  can 
the  force  of  the  waves.  In  some  cases,  however,  the 
ocean  currents,  sweeping  by  the  mouth  of  a  great  river, 
may  scatter  the  detritus  brought  down  by  the  river  far 
and  wide  over  the  neighboring  ocean  floor,  thus  prevent- 
ing the  building  of  a  delta.  It  is  largely  because  of  such 
work  by  currents  that  we  find  no  large  delta  in  front  of 
the  Amazon  River. 

Next  to  the  work  of  distributing  moisture  and  temper- 
ature, and  the  detritus  brought  by  rivers,  the  ocean  cur- 
rents are  important  because  they  keep  the  surface  waters 
of  the  ocean  in  motion,  thus  supplying  food  to  the 
mouths  of  the  animals  and  plants  that  live  attached  to 
the  ocean  floor,  and  are  dependent  upon  having  their 
food  brought  to  them.  It  has  been  found,  for  instance, 
that  where  the  other  conditions  are  favorable,  corals  grow 


TIDES. 


Ill 


most  rapidly  where  there  is  a  strong  ocean  current  that 
provides  abundant  food. 


TRANSATLANTIC  ROUTES. 


OCEAN  CURRENTS. 


FIG.     4g. — MAP   OF    PRINCIPAL    OCEAN    CURRENTS   AND   OCEAN    ROUTES  OP 
NORTH    ATLANTIC    OCEAN. 

Tides. — The  third  and  last  kind  of  motion  of  standing 
water,  best  seen  in  the  oceans,  but  also  to  be  found  in 
large  lakes,  is  that  known  as  the  tide,  which  is  due  to  a 


112  A   READER  IN  PHYSICAL   GEOGRAPHY. 

complicated  series  of  causes  too  difficult  for  study  by 
beginners.  In  general,  it  may  be  said  that  the  pull  of 
the  sun  and  moon*  causes  tides,  the  waters  of  the  oceans 
and  lakes  being  continually  heaped  up  beneath  the  moon. 
We  should  therefore  expect  high  tide  at  New  York  City 
when  the  moon  was  directly  in  the  south.  When  the 
moon  is  directly  opposite  us  on  the  other  side  of  the 
world,  we  have  another  high  tide;  and  when  it  is  half- 
way between  these  two  points  at  either  side,  we  have  low 
tide.  The  difference  in  height  between  the  level  of  the 
waters  at  high  tide  and  low  tide  off  Governor's  Island, 
New  York  City,  averages  4.5  feet;  at  New  London,  Con- 
necticut, there  is  a  difference  of  but  one  foot ;  and  at 
Boston,  Massachusetts,  the  range  of  height  is  from  eight 
to  ten  feet.  In  the  Bay  of  Fundy,  where  the  tides  are 
famous  for  their  work  and  strength,  there  is  a  range  in 
height  of  something  over  fifty  feet.  This  variation  in 
height  is  largely  due  to  the  character  of  the  coast  line 
against  which  the  water  comes. 

Where  the  water  of  the  tide  goes  in  and  out  through 
the  mouth  of  a  great  estuary  twice  a  day  in  either  direc- 
tion, it  rushes  with  tremendous  force,  and  may  do  a  large 
amount  of  erosive  work,  keeping  the  channel  scoured 
clean,  and  preventing  any  deposition  of  the  detritus 
brought  by  the  rivers  and  waves.  This  tidal  scour  is 
,very  important  in  keeping  many  harbors  clear  and  usable. 
Indeed,  the  principle  is  used  at  the  mouths  of  many 
rivers,  as,  for  instance,  in  the  case  of  the  Mississippi, 
where  the  water  is  forced  by  a  series  of  jetties  to  follow 
a  narrow  channel,  thus  keeping  the  bed  of  the  stream 
from  filling  up  with  fine  mud  or  silt. 

Although  the  tidal  scour  is  important  in  keeping  the 
harbors  from  filling  up,  and  thereby  of  great  value  to 


LAKES. 


such  a  city  as  New  York,  yet  in  some  ways  the  tide  is 
a  hindrance  to  commerce.  For  instance,  sailing-vessels 
find  it  difficult  to  make  any  headway  against  a  strong 
tide,  particularly  if  the  wind  be  light.  In  a  similar  way 
our  great  ocean  steamers,  owing  to  their  draught,  and 


FIG.  50. — A  LAKE  FORMED  BY  A  NATURAL  BARRIER  BUILT  ACROSS  A 
SMALL  STREAM  IN  NEW  HAMPSHIRE.  THE  LAKE  IS  SHOWN  AS 
FROZEN  INTO  AN  ICE  PLAIN. 

the  need  of  deep  water,  find  it  necessary  to  pass  in  and 
out  of  New  York  Harbor  on  the  incoming  or  flood  tide, 
rather  than  on  the  outgoing  or  ebb  tide. 

Lakes. — The  bodies  of  standing  water  held  up  stream 
by  some  rock  barrier  across  a  river's  course,  and  known 
as  lakes,  present  many  features  in  common  with  the 
larger  oceans.  (See  Fig.  50.)  The  work  of  waves  may 


114  A   READER  IN   PHYSICAL  GEOGRAPHY. 

produce  extensive  changes  on  the  shore  line,  and  give  us 
topographic  forms  very  similar  to  those  to  be  seen  on 
ocean  shores.  If  for  any  reason  the  lake  disappears,  the 
shore  lines,  the  cut  cliffs,  .and  benches  may  be  left  on 
the  hillsides  as  witnesses  to  the  former  presence  of  water. 
This  is  well  illustrated  in  many  places  in  New  York 
about  the  south  shore  of  Lake  Ontario,  and  also  about 


FIG.  51. — BEACHES  AND   CLIFFS   NEAR   SALT  LAKE   CITY,    UTAH,  AND    HIGH 
ABOVE   THE    PRESENT    LEVEL    OF    GREAT    SALT    LAKE. 


Great  Salt  Lake  in  Utah,  which  was  once  a  lake  many 
times  its  present  size,  and  several  hundred  feet  deeper. 
(See  Fig.  51.) 

The  lakes  which  are  very  frequently  found  above  a 
waterfall,  as  in  the  case  of  Lake  Erie,  up  stream  from 
Niagara,  are  often  of  great  importance  to  man.  They 
may  serve  as  natural  reservoirs,  holding  the  water  back 
so  that  it  does  not  run  all  at  once  to  the  sea  after  a  rain, 


LAKES.  115 

thus  giving  a  supply  of  water  that  maybe  used  for  drink- 
ing water  by  large  cities,  or  for  manufacturing  purposes. 
The  shore  of  a  large  lake  offers  a  very  favorable  situation 
for  summer  homes  (see  Fig.  50)  and  camping  places,  be- 
cause of  the  fresh,  cool  air,  the  beauty  of  the  scene,  and 
perhaps  the  fishing,  all  of  which  assist  in  making  a  lake  a 
pleasant  spot  near  which  to  live. 

The  series  of  great  lakes  along  the  northern  border  of 
the  United  States  offers  a  means  of  communication  by 
water  that  reduces  greatly  the  cost  of  transporting  goods 
that  are  not  perishable  from  the  interior  to  the  ocean 
ports.  As  water  does  not  warm  so  rapidly  in  the  sum- 
mer, or  cool  so  rapidly  in  the  winter  as  land,  large  lakes 
tend  to  make  the  climate  round  about  them  more  uni- 
form. At  the  eastern  end  of  Lake  Ontario,  for  instance, 
where  the  winds  blow  for  a  greater  part  of  the  year  from 
the  lake,  the  temperature  is  much  more  uniform  than  in 
the  adjacent  highlands  of  New  York  State,  which  have 
much  colder  winters.  As  the  wind  blows  from  the  lake, 
it  gathers  moisture,  forming  mists  or  clouds,  so  that  the 
region  spoken  of  has  many  more  cloudy  days  in  the  year 
than  can  be  found  in  any  other  part  of  the  State,  except 
round  about  New  York  City,  where  moisture  in  a  similar 
way  blows  in  from  the  sea. 

Finally,  lakes  are  important  because  they  allow  the 
detritus  brought  to  them  by  the  streams  to  settle,  so  that 
the  outgoing  streams  are  clear.  The  River  St.  Lawrence, 
as  it  flows  from  Lake  Ontario  through  the  Thousand 
Islands,  is  such  a  beautifully  clear  stream,  carrying  but 
little  detritus.  The  River  Rhone,  as  it  flows  into  Lake 
Geneva  in  Switzerland,  is  a  milk-white  stream,  full  of 
fine  ground  rock  gathered  from  the  glaciers;  and  this  is 
accumulating  as  a  delta  at  the  head  of  the  lake.  When 


Il6  A   READER  IN   PHYSICAL   GEOGRAPHY. 

the  River  Rhone  emerges  from  Lake  Geneva,  it  is  one  of 
the  clearest,  most  crystal  rivers  in  the  world,  because  its 
fine  silt  has  been  dropped  in  the  lake. 

Whenever  a  lake  bottom  is  revealed  by  the  filling  or 
drying  of  the  lake,  or  by  the  removal  of  the  barrier  that 
held  the  water  in,  the  fine  muds  of  the  bottom  of  the 
lake  are  exposed  as  a  level  plain,  very  rich  and  very  flat. 
(See  Fig.  52.)  In  Manitoba  and  North  Dakota  a  great 
lake  floor  has  been  recently  exposed,  and  in  the  soils  of 
this  old  lake  floor  are  raised  the  greatest  wheat  crops  of 


FIG.    52. — AN   EXPOSED     LAKE    BOTTOM    ABOUT    GREAT    SALT    LAKE,    UTAH. 

the  United  States,  and  among  the  greatest  in  the  world. 
(See  Fig.  53.) 

Summary. — We  have  already  seen  that  the  general 
effect  of  standing  water  is  to  cut  into  the  land  horizon- 
tally, making  cliffs  and  beaches;  perhaps  making  the 
shore  line  more  irregular  where  the  rocks  are  of  varying 
strengths,  and  regular  where  the  waves  and  currents  can 
build  long  and  unbroken  beaches.  The  area,  however, 
that  can  be  attacked  by  the  waves  and  tides  and  ocean 
currents  is  small  compared  to  the  area  of  the  world  that 
can  be  worn  by  the  atmosphere  and  running  water.  AD 


SUMMARY.  117 

parts  of  the  rock  surface  of  the  world  not  covered  by 
vegetation  and  by  ice  are  subjected  to  active  weathering; 
and  even  the  area  covered  by  vegetation  wears  slowly 
under  the  attack  of  the  erosive  forces  we  have  considered. 
The  forces  of  the  ocean,  however,  cannot  attack  the 
shore  except  between  the  limits  of  the  bottom  of  the 
waves  and  the  top  of  the  cliffs  reached  by  the  highest 
spray.  More  than  five  hundred  feet  below  sea  level  there 


FIG.    53. — A   FIELD    OF   FLAX   ON   THE   GREAT   DAKOTA   LAKE   FLOOR. 

is  probably  but  little  water  motion  and  water  work;  and 
above  a  height  of  one  hundred  feet  there  is  also  but  little 
water  work.  Thus  most  of  the  ocean  force  is  concen- 
trated on  the  very  coast  line.  The  area  thus  exposed  to 
water  work  is  very  narrow,  and  is  as  long  as  the  coast 
line  of  the  world,  which  is  many  thousand  miles.  This 
area,  however,  can  in  no  way  be  compared  in  size  with 
the  greater  area  attacked  by  running  water  and  the  atmos- 
phere, and  thus  in  a  given  time  we  must  expect  standing 


II 8  A   READER   IN   PHYSICAL  GEOGRAPHY. 

water  to  be  of  less  importance  as  an  eroding  agent  than 
are  the  other  forces. 

The  great  bodies  of  standing  water  that  we  see  in  the 
greater  oceans  and  seas  are  also  very  important  because 
they  are  the  receptacles  into  which  the  running  water  of 
the  world,  and  the  winds,  are  carrying  all  the  materials 
brought  from  the  land.  Thus  as  the  land  surfaces  are 
wearing  down,  the  oceans  are  filling  up  with  detritus 
brought  from  the  land.  As  the  land  surfaces  become 
rougher  under  the  attack  of  the  erosive  forces,  the  irregu- 
larities of  the  ocean  bottom  are  becoming  more  and  more 
covered  with  the  fine  muds  and  sands  brought  from  the 
land.  Were  these  processes  to  continue  uninterrupted, 
it  would  only  be  a  question  of  time  when  the  land  sur- 
faces would  be  worn  beneath  the  level  of  the  sea.  There 
is,  however,  another  series  of  forces  at  work,  counter- 
acting these  influences,  for  the  continents  are  continually 
rising  from  beneath  the  sea,  and  being  folded  into  moun- 
tains, presenting  thus  a  new  supply  of  land  to  the  forces 
that  are  wearing  it  away,  and  making  it  possible  for  land 
life  to  continue. 


CHAPTER   XL 

THE   WORK   OF    ICE   AND   FROST. 

THE  fourth  and  last  great  way  in  which  the  surface  of 
the  earth  is  changed  in  shape  is  through  the  work  of 
water  in  its  solid  forms — that  is,  as  ice,  snow,  and  frost. 
In  temperate  regions,  such  as  ours,  the  work  of  snow  and 
frost  is  ordinarily  seen  each  winter,  when  we  have  about 
us  good  illustrations  of  conditions  in  the  so-called  frigid 
zones.  On  the  tops  of  very  high  mountains,  even  in  the 
tropical  regions  of  the  world,  and  around  the  north  and 
south  poles,  snow  and  ice  exist  continually,  melting  away 
a  little  in  the  summer,  but  never  disappearing.  In  such 
regions,  where  the  work  is  continual,  it  is  natural  to  ex- 
pect that  the  erosive  work  of  ice  must  be  important. 

Effect  on  Life — The  animals  and  plants  in  the  tem- 
perate region  live  a  life  that  is  more  or  less  arranged  to 
withstand  the  cold  and  frost  of  the  winter.  Plants  cease 
their  growing  and  perhaps  die,  the  life  of  the  plant 
remaining  over  to  the  next  season  in  the  seed,  which  is 
not  injured  by  frost;  the  sap  of  many  trees  retires  to 
the  roots,  and  some  trees  may  freeze  through  with- 
out being  hurt.  Many  animals  retreat  into  burrows,  or 
some  other  retired  spot,  and  rest,  or,  as  we  say,  hiber- 
nate, during  the  winter,  as  may  be  illustrated  by  the 
thousands  of  bats  that  inhabit  Mammoth  Cave  in  Ken- 
tucky, or  by  the  flies  that  may  be  found  sometimes  by 
the  handful  in  unused  boxes  in  country  attics.  Other 
animals,  such  as  the  ranch  cattle,  grow  thick  coats,  and 


120 


A   READER  IN   PHYSICAL   GEOGRAPHY. 


manage  to  exist  in  the  open  weather,  feeding  on  what- 
ever shrubs  or  roots  or  seeds  are  available.  Some  ani- 
mals, like  the  English  sparrow,  are  so  hardy  that  they 
seem  to  pay  no  attention  to  frost  and  snow. 

Effect  on  Rocks. — The  work  of  frost  and  snow  is  also 
important  in  its  effect  on  the  rocks  of  the  earth.     (See 


FIG,  54. — ROCKS  ON  THE  SUMMIT  OF  PIKES  PEAK,  COLORADO,  BROKEN 
BY  FROST.  THE  WHITE  PATCH  IS  ICE  THAT  REMAINS  THROUGH 
THE  SUMMER. 

Fig.  54.)  The  farmer  knows  very  well  that  if  he  ploughs 
his  land,  and  turns  the  deeper  and  larger  soil  particles  to 
the  surface  before  winter  sets  in,  the  water  penetrating 
into  the  cracks  of  the  stones  will,  in  freezing,  split  them 
in  pieces,  making  it  much  easier  to  prepare  the  soil  for 
planting  in  the  spring.  An  indirect  effect  of  snow  and 
ice  is  seen  in  the  frequent  and  serious  spring  floods 


GLACIERS.  121 

caused  by  the  sudden  melting  of  the  water  that  has  been 
locked  up  in  a  solid  form  as  snow  or  ice  on  the  hillsides 
and  mountain  tops  during  the  long  winter  season.  When 
the  frozen  ground  melts  in  the  springtime,  the  soil  is  full 
of  moisture,  and  is  usually  very  muddy.  If  the  soil  lies 
on  a  steep  slope,  there  may  be  small  landslides,  produced 
by  the  slipping  of  the  soil  down  hill.  Farmers  in  New 
England  and  New  York  expect  to  see  their  stone  fences 
undermined  and  tumbled  down  through  the  work  of  the 
spring  thaws  following  the  long  winter  frost,  and  the 
Farmers'  Almanack  for  March  and  April  usually  includes 
such  advice  as,  "  Now  is  a  good  time  to  repair  fences 
that  have  been  weakened  during  the  winter." 

Snow. — Although  frost  and  ice  may  damage  plants 
and  animals  to  a  certain  extent,  a  deep  layer  of  snow 
lying  over  the  grass  roots  and  around  the  trees  is  a  great 
protection,  as  it  keeps  the  roots  from  freezing  and  thaw- 
ing with  each  sudden  change  of  temperature.  Rabbits 
and  mice  may  live  comfortably  in  the  snow;  and  fre- 
quently, when  the  snow  melts  in  the  springtime,  one 
finds  the  streets  of  a  mouse  city,  made  by  the  mice  as 
they  have  burrowed  through  the  snow  on  their  way  to 
roots  and  bark  that  would  furnish  them  food. 

Glaciers. — As  has  been  suggested,  snow  exists  in  cer- 
tain parts  of  the  world  the  year  round.  As  it  lies  on  the 
land  from  year  to  year,  it  may  accumulate  in  great 
masses,  and  under  the  accumulating  pressure  of  the  new 
layers  may  be  slowly  pressed  into  blue  ice,  just  as  a 
boy  makes  a  solid  icy  snowball  by  pressing  together  fine 
white  snow  until  the  air  is  pressed  out.  Such  accumula- 
tions of  ice  and  snow  are  known  as  glaciers  (see  Fig.  55), 
and  are  found  in  Alaska,  Greenland,  Northwestern  Can- 
ada, Norway  and  Sweden,  Switzerland,  New  Zealand, 


122  A   READER   IN   PHYSICAL   GEOGRAPHY. 

and  certain  other  parts  of  the  world.  The  glaciers  do 
not  remain  on  the  sides  and  tops  of  the  mountains  where 
the  snow  has  accumulated,  but  slowly  flow  down  toward 
the  adjoining  lowlands,  very  much  as  a  mass  of  heavy 
pitch  or  molasses  candy  would  slowly  flow  down  a  slop- 
ing trough.  As  a  result,  glaciers  may  be  found  far  within 


FIG.   55. — THE  MARGIN  OF  THE  DAVIDSON  GLACIER,  ALASKA.      NOTE   ALSO 
THE    PERPETUAL    SNOW    ON    THE    MOUNTAIN    TOPS. 


the  region  where  the  snow  does  not  lie  throughout  the 
year,  as,  for  instance,  in  Switzerland,  where  the  glaciers 
push  down  the  valleys  between  the  bare  hillsides  which 
are  miles  away  from  the  snow-covered  mountains.  The 
glaciers  push  into  the  warmer  regions,  until  finally  the 
heat  is  great  enough  to  melt  them  back  as  fast  as  they 
push  forward.  If  the  melting  back  is  more  rapid  than 
the  advance  of  the  glacier,  the  front  of  the  glacier  is 


GLACIERS. 


I23 


pushed  farther  and  farther  up  stream,  or,  as  it  is  some- 
times stated,  the  glacier  retreats.  The  water  furnished 
by  the  melting  of  the  ice  forms  rivers,  sometimes  flowing 


FIG.    56. — MOUTH    OF    A    STREAM    FLOWING    FROM    BENEATH    A    GLACIER    IN 

ALASKA. 


from  under  the  ice,  and  always  present  at  the  front  of  a 
melting  ice  sheet.     (See  Fig.  56.) 

In  some  cases  the  glaciers  push  directly  into  the  ocean, 
as  in  Alaska  (see  Figs.  55  and  57),  and  then  the  great  ice 
mass  breaks  up  into  smaller  pieces  that  float  away  as 
icebergs,  until  finally  they  are  melted  in  the  warm  waters 


124  A   READER   IN   PHYSICAL   GEOGRAPHY. 

of  the  ocean  through  which  they  travel.  The  captains  of 
ocean  steamers  running  between  the  British  Isles  or  Ger- 
many and  New  York  frequently  report  icebergs  during 
the  spring  and  summer  months.  Though  icebergs  move 
but  slowly,  they  are  dangerous  objects  in  the  ocean,  as 
they  have  force  enough,  owing  to  their  size  and  weight, 


FIG.    57. — MUIR    GLACIER,    ALASKA,    SHOWING    MELTING   EDGE   AND    SMALL 
ICEBERGS.       NOTE    ROCK    ISLAND    SURROUNDED    BY    ICE. 

to  crush  any  small  object,  like  a  steam  vessel,  with  which 
they  come  in  contact. 

Review. — A  glacier,  then,  is  a  moving  mass  of  ice 
and  snow,  pushing  from  the  region  in  which  it  has  accu- 
mulated, outwards  and  downwards  toward  warmer  areas. 
The  glacier  is  not,  like  a  river,  confined  to  any  one  small 
channel  in  a  valley,  but  covers  the  whole  valley  to  a 
nearly  uniform  depth,  and  consequently  affects  a  large 
amount  of  land  in  its  motion.  In  Greenland  practically 


EROSIVE   WORK   OF   ICE.  125 

the  whole  island  is  covered  with  ice,  giving  us  a  great  ice 
plain.  In  most  regions  where  glaciers  occur  they  are 
found  only  on  mountain  tops  and  in  the  radiating  valleys. 
These  are  known  as  valley  or  Alpine  glaciers.  From  the 
study  of  such  Alpine  glaciers,  Professor  Louis  Agassiz 
showed  that  many  of  the  surface  features  of  Europe  and 
America  could  have  been  formed  only  by  the  former 
work  of  ice.  Other  people  are  now  as  convinced  as  he 
was  that  an  ice  sheet  so  large  as  to  be  called  a  continen- 
tal glacier  once  covered  North  America  as  far  south  as 
New  York.  Let  us  look  at  some  of  the  facts  that  led 
Agassiz  and  others  to  this  opinion. 

Erosive  Work  of  Ice. — An  enormous  mass  of  ice  such 
as  a  continental  glacier,  moving  over  the  land,  must,  by 
its  rubbing,  produce  a  great  deal  of  change  on  the  land 
surface.  Picking  up  the  small  rock  particles  that  are 
easily  loosened,  it  scrapes  them  along  in  the  direction  of 
its  motion,  grinding  them  against  the  rock  beneath  until 
the  rubbed  rock  becomes  scratched  and  smooth  (see 
Fig.  58),  and  the  grinder  partly  or  wholly  worn  away. 
The  general  effect  is  very  much  like  that  of  a  laundress 
in  smoothing  a  bit  of  linen ;  a  flat-iron  smooths  out  all 
the  roughnesses,  but  if  there  be  a  particle  of  dirt  on  the 
flat-iron  there  will  be  a  scratch  or  a  streak  running  in  the 
direction  of  motion,  and  leaving  a  slight  depression  below 
the  general  smooth  level  of  the  linen.  This  grinding  work 
of  the  ice  is  very  important,  because  all  the  surface  over 
which  the  ice  glides  offers  small  tools  for  the  ice  to  use 
as  grinders.  As  the  rock  material  thus  acquired  is  rubbed 
and  rolled  along  by  the  ice,  it  must  of  necessity  be  ground 
finer  and  finer,  or,  as  we  sometimes  say,  made  into  "  rock 
flour,"  just  as  corn  or  wheat  in  a  mill  is  made  finer  the 
longer  it  is  ground.  Such  fine  rock  flour  gives  the  milky 


126  A   READER  IN   PHYSICAL  GEOGRAPHY. 

color  to  the  streams  that  flow  from  beneath  glaciers,  as 
has  been  noted  in  reference  to  the  River  Rhone. 

In  some  cases  the  ice  cannot  grind  down  all  the  irregu- 
larities of  the  land  surface,  but,  moving  around  a  great 
mass  of  rock,  may  pluck  it  out  and  bear  it  along  as  a 


FIG.    58. — A  GLACIALLY    SCRATCHED  AND  SMOOTHED    SURFACE  AT  MARBLE- 
HEAD.    MASSACHUSETTS. 

tremendous  boulder;  so  that  fine  and  coarse  materials  are 
mixed  in  a  confused  mass,  all  going  forward  together. 
As  the  glacier  may  get  its  materials  from  any  spot  up 
stream,  there  is  naturally  -a  great  variety  of  particles  in 
the  detritus  that  is  being  carried  along. 

Transportation    Work    of    Ice. — The    material    thus 
eroded  from  the  land  becomes  a  load  for  the  ice  to  push 


DEPOSITS   MADE   BY   ICE. 


127 


or  carry  forward.  This  is  not,  however,  the  only  source 
of  load,  for  the  glacier  gets  also  a  large  contribution  of 
materials  from  any  land  that  may  project  above  the  ice, 
from  which  avalanches  and  landslides  are  very  liable  to 


FIG.  59. — THE  ROCKING  STONE  IN  THE  NEW  YORK  ZOOLOGICAL  PARK. 
THE  STONE  RESTS  ON  A  SCRATCHED  SURFACE. 


dump  materials  on  the  ice  at  almost  any  time.  Like 
running  water  and  standing  water,  glaciers  carry  their 
loads  as  long  as  their  strength  will  permit. 

Deposits  Made  by  Ice. — The  deposits  of  detritus 
formed  by  the  ice  may  be  made  in  some  cases  beneath 
the  ice,  and  in  some  cases  in  front  or  at  the  side  of  the 


128 


A   READER  IN   PHYSICAL   GEOGRAPHY. 


ice  mass.  As  the  ice  melts  away,  of  course  these  parti- 
cles slowly  settle,  until  finally,  the  prop  which  has  held 
them  up  being  gradually  removed,  they  come  to  rest  on 
the  solid  rock  bottom,  without  any  perceptible  jar. 
Large  boulders  are  very  frequently  deposited  in  this 
manner,  perhaps  on  the  top  of  a  good-sized  hill,  and  in 


FIG.    60. — A   BOULDER   MORAINE    IN    RHODE   ISLAND. 

such  a  position  that  they  may  be  rocked  to  and  fro,  but 
not  overturned.  The  famous  Rocking  Stone  of  the  New 
York  Zoological  Park  is  an  excellent  illustration  of  such 
a  boulder.  (See  Fig.  59.) 

The  mixed-up  accumulations  of  mud,  clay,  boulders, 
etc.,  dumped  in  an  irregular  confused  heap,  where  the 
ice  retreats  from  the  sides  of  the  valley,  or  where  it 
melts  at  its  front,  are  known  as  moraines.  When  first 


DEPOSITS   MADE   BY   ICE. 


I29 


formed  they  are  very  rough  and  irregular,  perfectly  bar- 
ren of  vegetation,  and  covered  over  with  large  and  small 
boulders  (see  Fig.  60),  and  perhaps  dotted  with  innumer- 
able lakes  that  lie  in  the  hollows.  Such  are  the  features 
of  the  moraines  now  being  formed  in  Alaska,  and  except 
for  the  presence  of  vegetation  which  has  recently  formed, 


FIG.  6l. — AN    ACCUMULATION    OF    TILL  NEAR  ST.   PAUL,  MINNESOTA.       NOTE 
VARYING    SIZE    OF    PARTICLES    AND    UNDERLYING    SOLID    ROCK. 

such  are  the  features  of  those  parts  of  the  United  States, 
particularly  Marthas  Vineyard,  Nantucket,  Long  Island, 
and  Staten  Island,  that  are  moraines  formed  by  the  great 
glacier  that  once  covered  this  part  of  the  country.  The 
materials  of  such  moraines  are  known  as  till.  (See  Fig. 
61.)  The  soil  is  very  rich,  because  of  its  variety  of  con- 
tents;  but  it  is  hard  to  cultivate,  owing  to  the  great 
9 


130  A  READER  IN  PHYSICAL  GEOGRAPHY, 

number  of  large  boulders  that  may  cover  it.     (See  Fig. 

62.) 

In  some  cases  the  till  was  apparently  overridden  by  the 
advancing  ice,  very  much  as  the  snow  in  front  of  a  snow- 
pusher  may  suddenly  be  overridden  and  smoothed  and 


FIG.    62. — A    GLACIATED    FIELD    IN    IRELAND.       MANY    OF    THE    BOULDERS 
HAVE    BEEN    REMOVED    IN   BUILDING   THE    HOUSE. 

shaped  by  the  pusher,  so  that,  instead  of  irregular  till 
hills,  we  have  smoothed  and  symmetrical  hills.  In  West- 
ern and  Central  New  York,  in  Massachusetts,  and  in  Wis- 
consin particularly  there  are  great  numbers  of  such  regu- 
lar hills,  commonly  known  as  drunilins  (see  Fig.  63),  and 
having  very  much  the  shape  of  half  a  foot-ball.  Their 
longest  dimension  usually  runs  in  the  direction  of  the  ice 


DEPOSITS   MADE  BY   ICE.  13! 

motion,  as  shown  by  their  being  parallel  to  the  ice  scratches 
which  may  be  found  on  the  solid  rock  in  their  vicinity. 

All  the  material  worn  away  from  the  earth  and  carried 
forward  by  the  ice  is  not,  however,  necessarily  deposited 
by  the  ice  itself.  The  melting  ice  of  the  glacier  furnishes 
much  water,  which  may  run  on  the  surface  as  streams, 
until  finally  it  goes  through  some  crack  and  disappears 
to  join  the  stream  of  water  which  is  flowing  beneath  the 
glacier.  (See  Fig.  56.)  Such  streams,  which  accompany 


FIG.     63. — A    DRUMLIN    IN    MASSACHUSETTS.        THIS    DRUMLIN    IS    BEING 
WORN   AWAY   BY   THE   OCEAN   AT   THE   LEFT   END. 

all  glaciers,  and  which  must  have  been  very  numerous 
along  the  front  of  the  great  glacier  that  once  covered 
North  America,  carry  forward  a  great  quantity  of  detri- 
tus in  their  grasp.  The  water  of  the  streams,  while  it  is 
flowing  beneath  the  ice,  being  under  the  pressure  of  the 
mass  of  ice  above,  very  much  as  the  water  in  a  street 
hydrant  is  pressed  by  the  weight  of  water  in  a  distant 
reservoir  and  pipes,  often  bursts  from  the  front  of  the 
glacier  with  tremendous  force,  making  perhaps  great  ice- 
water  fountains. 


132  A   READER  IN   PHYSICAL  GEOGRAPHY. 

As  the  water  comes  out  into  the  open  air,  its  carrying 
power  is  suddenly  lessened,  and  the  rock  materials  that 
have  been  banged  about  and  rounded  as  they  have  been 
carried  forward  are  deposited  almost  immediately  at  the 
front  of  the  moraines.  In  this  way  ice-brought  materials 
are  carried  beyond  the  limits  of  the  region  occupied  by 
the  glacier,  and  cover  over  the  adjoining  country,  fre- 
quently forming  a  great  plain  such  as  the  plain  that 
slopes  away  from  the  southern  edge  of  the  Long  Island 
moraine  toward  the  sea.  The  sands  and  gravels  that  are 
frequently  found  in  hollows  high  up  in  the  hills  of  New 
England  and  New  York  were  deposited  by  the  streams 
of  running  water  which  flowed  into  temporary  lakes, 
formed  as  the  ice  front  slowly  melted  back.  The  fine 
soils  that  have  been  mentioned  before,  in  the  great  wheat 
regions  of  Dakota  and  Manitoba,  were  formed  as  silt  in 
the  bottom  of  a  lake  that  was  in  part  held  in  by  the  great 
glacier,  and  are  made  largely  from  the  materials  brought 
by  the  glacier. 

The  Work  of  the  Great  Ice  Sheet.— I  have  suggested 
that  a  glacier  once  covered  northern  North  America  as 
far  south,  in  the  eastern  part  of  the  United  States  at  least, 
as  the  latitude  of  New  York  City.  We  know  this  because 
the  conditions  of  soil,  and  the  shapes  and  character  of  the 
hills  north  of  this  line,  are  similar  in  almost  everyway  to 
the  soil  and  earth  forms  made  by  the  much-studied  and 
famous  glaciers  of  Greenland,  Alaska,  and  Switzerland. 
In  the  glaciated  region  we  find  lakes  by  the  thousand, 
some  of  them  now  changed  into  peat  bogs,  or  filled  with 
vegetation  and  rubbish,  so  that  they  have  become  dry 
and  tillable  land.  We  also  find  the  soil  in  the  valleys 
made  up  of  all  kinds  and  sizes  of  materials,  often  accu- 
mulated to  a  great  depth,  while  the  adjoining  hillsides 


THE   WORK   OF  THE   GREAT  ICE   SHEET.  133 

have  but  a  thin  coating  of  soil,  and  the  bare  rocks  are 
covered  with  scratches  and  smoothed  and  rounded  very 
evidently  by  some  moving  body.  The  larger  rivers  fol- 
low valleys  that  were  very  evidently  partly  made  before 
the  ice  occupied  the  country,  as  the  valleys  are  covered 
with  ice  deposits  through  which  the  rivers  are  running  as 
best  they  can.  Oftentimes  where  the  deposits  were 
dumped  irregularly  over  the  former  valley  bottom, under- 
lying masses  of  hard  rock,  little  promontories  that  pro- 
jected into  the  former  valley,  were  covered.  The  river, 
cutting  down  into  the  glacial  deposits,  in  time  strips  away 
the  overlying  soil,  and  then  may  find  itself  cutting  across 
such  a  hard  rock  barrier,  making  a  waterfall  or  a  rapid. 
Such  is  the  origin  of  thousands  of  waterfalls  and  rapids 
in  New  England  and  New  York.  (See  Fig.  64.) 

Furthermore,  we  often  find  boulders  which  can  be 
traced  back  to  the  hill  from  which  they  were  plucked, 
but  which  are  now  perhaps  miles  from  their  place  of 
origin,  and  at  rest  upon  rocks  that  are  in  no  way  like 
them.  For  instance,  on  Manhattan  Island  and  on 
Staten  Island,  New  York,  very  many  large  and  small 
boulders  may  be  found  which  are  made  of  rock  found 
nowhere  east  of  the  Hudson  Riven  They  must,  there- 
fore, have  been  brought  across  the  Hudson  by  some 
force  that  could  carry  them  uphill,  and  leave  them  very 
delicately  poised,  perhaps  on  the  very  top  of  a  hill.  On 
the  island  of  Marthas  Vineyard  boulders  have  been 
found  that  could  only  have  come  from  one  particular  hill 
about  sixty  miles  away  in  a  straight  line,  in  the  vicinity 
of  Providence,  Rhode  Island.  Such  boulders  give  us  a 
clue  to  the  great  distance  that  rock  detritus  may  be  car- 
ried by  a  glacier,  without  being  worn  out. 

If  we  go  south  of  the  region  of  New  York,  we  find  a 


134  A   READER  IN   PHYSICAL   GEOGRAPHY. 

very  different  condition  of  affairs.  Lakes  are  almost 
entirely  absent,  the  soils  are  not  mixed-up  accumulations 
of  everything,  but  are  like  the  rocks  underneath,  from 
which  they  have  been  made  by  slow  decay.  Ice  scratches 
are  absent ;  transported  boulders,  except  those  that  have 


FIG.  64. — PORTAGE  FALLS  ON  THE  GENESEE  RIVER,  NEW  YORK.  THE 
RIVER  HAS  CUT  THROUGH  THE  OVERLYING  GLACIAL  DEPOSITS  WHICH 
MAY  BE  SEEN  IN  THE  BANKS. 

tumbled  down  from  some  cliff  under  the  pull  of  gravity 
or  have  been  rolled  down  a  valley  by  a  river,  are  un- 
known; the  hilltops  may  be -covered  with  soil,  and  in 
some  cases  one  may  have  to  dig  a  great  many  feet  before 
he  can  reach  solid,  unweathered  rock. 

In  every  way  the  evidence  is  strong  that  the  erosive 


SUMMARY.  135 

processes  of  the  atmosphere  and  the  running  water  have 
been  at  work  for  a  very  long  time,  uninterrupted  by  any 
such  great  accident  as  the  oncoming  of  the  glacier.  It  is 
from  the  careful  study  of  such  facts  as  these  that  we  have 
been  able  to  determine  the  area  formerly  covered  by  the 
ice,  and  to  reproduce  in  our  imagination  some  of  the 
conditions  which  existed  when  the  glacier  was  here. 
Glacial  work  is  the  only  great  erosive  force  that  we  can- 
not see  operating  actively  about  us,  and  yet  it  is  the 
force  that  has  changed  and  shaped  the  surface  of  the 
earth  in  our  immediate  vicinity  more  than  any  other, 
and  on  the  forms  01  land  made  by  the  ice  we  are  very 
largely  dependent  for  our  means  of  living. 

Summary. — The  general  result  of  the  several  kinds  of 
work  that  we  have  been  considering  is  the  cutting  of  any 
land  mass  into  valleys  and  hills,  and  the  general  lowering 
of  that  land  toward  the  level  of  the  sea,  through  the 
removal  of  the  loosened  detritus  in  the  ways  we  have 
suggested.  The  changes  thus  brought  about  are  made 
on  the  very  surface  of  the  earth,  and  take  place,  of 
course,  very  slowly.  Could  man  live  long  enough  in  one 
spot,  however,  he  would  be  able  to  see  that  century  after 
century  the  amount  of  change  would  accumulate,  so  that 
after  a  very  long  time  the  land  would  be  very  different 
from  its  original  form.  In  other  words.,  the  land  features, 
in  time,  grow  old,  and  finally  they  may  be  worn  down 
close  to  the  level  of  the  sea,  the  rocks  that  have  existed 
in  the  hills  and  mountains  having  been  removed  bit  by 
bit  to  a  new  resting-place  beneath  the  ocean. 

Land  forms  thus  have  a  history,  and  their  appearance 
at  any  time  depends  upon  their  age  and  the  experience 
they  have  had  in  life,  just  as  we  may  tell,  from  the  wrin- 
kles in  a  man's  face  and  from  his  general  air,  something 


136  A   READER  IN   PHYSICAL   GEOGRAPHY. 

of  his  age  and  experience.  As  in  man  the  wrinkles  and 
changes  are  but  surface  features,  and  are  determined  in 
their  character  by  the  underlying  skeleton  of  the  face,  so 
in  the  land  forms  the  hills  and  valleys  that  are  formed 
and  developed  during  the  processes  of  change  are  deter- 
mined in  their  character  by  the  kind  of  land  form  in 
which  they  have  been  cut  and  developed.  In  other 
words,  if  we  look  beneath  the  surface  features  made  by 
the  thin  layer  of  soil,  it  will  not  be  difficult  to  see  that 
each  land  form  has  a  certain  skeleton,  varying  in  char- 
acter according  to  the  way  the  mass  of  land  was  first 
accumulated  as  rock,  and  later  revealed  on  the  surface  of 
the  earth,  to  be  attacked  by  the  erosive  forces. 


THE  GREAT   LAND   FORMS. 

CHAPTER    XII. 
PLAINS    AND   PLATEAUS. 

WE  have  already  seen  that  most  of  the  rocks  of  the 
continents  have  been  formed  .beneath  the  sea  in  layers, 
and  afterwards  raised  or  tilted  or  crumpled  until  they 
have  come  above  the  sea  level  and  become  part  of  the 
continent.  In  other  cases  the  rocks  have  been  poured 
out  in  a  liquid  condition  upon  the  surface  of'  the  earth 
through  volcanic  openings,  and  have  there  cooled  or 
frozen  into  a  permanent,  solid  form.  In  still  other,  cases 
the  liquid  rocks  have  cooled  and  hardened  far  down  in 
the  earth,  and  are  now  exposed  through  the  slow  removal 
of  the  cover  that  formerly  protected  them.  In  general, 
such  large  and  extensive  forms  added  to  the  continents 
in  the  ways  suggested  may  be  grouped  into  plains, 
plateaus,  mountains,  and  volcanoes.  The  greater  land 
forms  of  the  world  belong  in  one  of  these  four  groups; 
but  the  general  features  that  any  particular  area  presents 
to  us  now  depend  on  the  amount  of  change  or  aging 
that  that  area  has  undergone  since  it  first  became  a  part 
of  the  continent. 

Plains. — The  first  and  most  important  of  these  great 
land  forms  are  plains,  of  which  a  good  example  is  the 
great  coastal  plain  (see  Fig.  65)  which  has  recently  risen 


138 


A  READER   IN   PHYSICAL  GEOGRAPHY. 


from  beneath  the  Atlantic  Ocean,  and  which  now  borders 
the  American  continent  in  a  broad  stretch  extending  from 
New  York  southward  along  the  Atlantic  coast  and  around 
the  Gulf  coast  far  into  Mexico.  Should  we  follow  this 
plain  by  soundings  beneath  the  level  of  the  ocean,  we 
would  find  it  sloping  equally  gently  for  about  a  hundred 
miles  off  shore  until  we  came  to  the  edge,  where  the 


FIG.  65.— A  BIT  OF  THE  COASTAL  PLAIN  IN  MARYLAND,  SHOWING 
GENERAL  CHARACTER  OF  A  YOUNG  PLAIN. 

depth  would  increase  very  rapidly.  This  unexposed  part 
of  the  coastal  plain  is  known  as  the  continental  shelf y  on 
which  the  detritus  of  the  continent  is  now  accumulating 
and  forming  into  layers,  perhaps  later  to  be  added  to  the 
continent,  thus  widening  the  coastal  plain. 

This  plain  throughout  its  greater  extent  consists  of  a 
broad  upland,  sloping  gently  from  the  older  land  in  the 
interior  of  the  continent  to  the  seashore.  The  rivers 
that  run  across  the  coastal  plain  have  cut  shallow,  some- 


PLAINS. 


139 


what  steep-sided  valleys  into  the  plain,  not  large  enough, 
however,  to  be  the  seat  of  occupation.  Riding  across 
the  plain,  one  would  not  be  aware  of  the  valleys  until  he 
came  to  the  very  edge.  Such  a  stage  of  development 
may  be  illustrated  very  well  in  New  Jersey  and  Mary- 
land, and  we  may  well  speak  of  such  a  plain  as  being 


FIG.    66. — A  YOUNG  VALLEY  IN    ALABAMA.       NOTE  THE  STEEP- 
NESS   OF    SLOPES    AND    NARROWNESS    OF    VALLEY    BOTTOM. 


youthful  in  character,  for  not  much  of  the  upland  surface 
has  yet  been  removed.  On  the  upland  the  people  live, 
devoting  their  attention  mostly  to  agriculture,  made  pos- 
sible through  the  richness  of  the  soil  of  the  weak  rocks 
of  the  plain. 

Had  this  plain  been  elevated  much  higher  when  it  was 
added  to  the  continent,  the  river  valleys  would  have  been 
cut  much  deeper,  and  the  chances  of  tributaries  to  be 


140  A   READER   IN   PHYSICAL   GEOGRAPHY. 

developed  would  have  been  much  greater,  so  that  the 
country  would  have  been  entirely  cut  up  into  hills  and 
valleys,  and  by  this  time  perhaps  very  little  of  the  upland 
left.  We  might  then  say  that  the  plain  would  be  middle 
aged.  As  the  hills  gradually  wear  down  in  the  later  life 
of  a  plain,  the  topography  would  be  more  rolling,  less 
uneven,  and  the  country  would  be  old.  These  several 
stages  of  age  in  plains,  together  with  all  the  other  stages 
of  development,  can  be  illustrated  by  watching  the  rapid 


FIG.    67. — THE   NIAGARA  RIVER  ABOVE   NIAGARA  FALLS,  FLOWING  ACROSS 
A    FLAT    PLAIN. 

wearing  away  of  a  small  plain  made  in  a  mud  puddle 
during  a  rapid  and  heavy  rain.  If  we  look  at  the  mud- 
puddle  plain  as  the  representative  of  a  great  continent 
plain,  and  watch  the  movements  of  the  ants  crawling 
over  it,  and  see  how  they  are  hindered  by  the  increasing 
roughnesses  of  the  plain  as  it  grows  middle  aged,  and 
how  they  are  aided  by  the  smoothness  of  old  age,  we  can 
get  something  of  an  idea  of  the  way  men  may  be  hin- 
dered or  aided  in  their  life  by  the  roughness  or  smooth- 
ness of  the  land  on  which  they  live. 


PLATEAUS.  141 

A  plain  may  be  defined  as  a  broad,  gently  sloping  area 
bordered  by  higher  lands  on  one  or  both  sides.  The 
Atlantic  Coastal  Plain,  which  has  been  mentioned,  is  bor- 
dered by  higher  land  to  the  west  in  the  Appalachians; 
the  Great  Central  Plain  of  the  United  States  and  Canada, 
extending  from  the  eastern  Appalachian  Highlands  to 
the  western  Cordilleran  Highlands,  is  a  good  illustration 
of  a  great  plain  bordered  on  both  sides  by  higher  lands. 
(See  Fig.  67.) 

Plateaus — Certain  parts  of  the  country,  particularly 
in  the  region  drained  by  the  Colorado  and  Columbia 
rivers  of  our  great  West,  and  in  the  so-called  Alleghany 
Mountains  of  the  fiast,  are  known  as  plateaus.  In  many 
ways  their  features  are  similar  to  those  of  plains,  except 
that  their  altitude  is  relatively  great,  and  that  one  ascends 
to  or  descends  from  them  rapidly.  In  the  case  of  the 
Alleghany  Plateau  we  have  a  broad,  nearly  flat-topped 
stretch  of  land,  in  sqme  cases  more  than  twenty  miles 
wide,  that  rises  abruptly  from  the  great  valley  of  the 
Tennessee  River  on  the  east,  and  also  from  the  lowland 
on  the  west.  In  the  case  of  the  Colorado,  one  ascends 
to  the  plateaus  by  climbing  up  the  very  steep  slope  on 
at  least  one  side,  and  perhaps  then  descends  very  grad- 
ually on  the  other.  As  a  plain  is  found  to  be  bordered 
on  at  least  one  side  by  rapidly  rising  higher  land,  so  the 
plateau  is  found  to  be  bordered  on  at  least  one  side  by  a 
steep  descent.  In  some  cases  this  descent  is  equally 
abrupt  on  both  sides. 

The  amount  of  upland  in  the  cas.e!  of  any  plateau 
depends,  as  in  a  plain,  on  the  number  and  size  of  the  river 
valleys  that  have  been  cut  into  it  since  it  was  elevated. 
In  the  southern  portion  of  the  Alleghany  Mountains,  in 
the  so-called  Cumberland  Plateau,  the  river  valleys  are 


142  A  READER  IN   PHYSICAL   GEOGRAPHY. 

few  and  small ;  one  can  ride  miles  on  horseback  straight 
across  country  without  crossing  any  ravines  of  any  size, 
and  paying  no  attention  to  roads.  In  the  northern  part 
of  the  same  region,  in  West  Virginia,  where  the  plateau 
is  known  as  the  Alleghany  Plateau,  the  river  valleys  are 


FIG.    68.— THE  VALLEY   OF  NEW   RIVER,  WEST  VIRGINIA,  SHOWING   STEEP 
SLOPES   OF   A    YOUTHFUL   VALLEY    CUT    INTO    A    PLATEAU. 

much  more  numerous,  and  are  mostly  steep  and  narrow. 
(See  Fig.  68.)  Here  the  amount  of  upland  has  been 
greatly  reduced,  and  the  country  is  one  of  ups  and 
downs.  Cross-country  travelling  is  therefore  difficult, 
and  the  people  must  live  on  the  slopes  or  in  the  bottoms 
of  the  river  valleys  rather  than  on  top  of  the  plateau. 


PLATEAUS.  143 

as  in  the  case  of  the  southern  Cumberland.  In  both  in- 
stances heavy  forests  cover  the  hilltops  and  valley  sides. 
In  the  Cumberland  region  there  are  few  settlers,  owing  to 
the  fact  that  the  region  is  somewhat  inaccessible  to  any 
large  towns ;  the  people  are  therefore  very  much  depend- 
ent upon  their  own  resources,  produce  most  of  the  neces- 
saries of  life,  and  devote  their  attention  largely  to  grazing, 
in  spite  of  the  fact  that  beneath  the  surface  of  the  earth 
there  is  a  very  great  quantity  of  coal,  which  makes  this 
area  one  of  great  mineral  richness.  The  coal,  however, 
cannot  be  readily  worked,  because  it  is  covered  by  a 
heavy  and  strong  layer  of  rock  that  makes  mining  diffi- 
cult and  expensive.  In  the  Alleghany  region,  however, 
where  the  river  valleys  are  numerous,  the  layers  of  coal 
are  exposed  all  along  the  sides  of  the  valleys,  so  that  it 
is  an  easy  task  to  dig  the  coal  from  the  earth.  As  a 
result,  the  country  is  thickly  occupied  with  mines,  and 
mining  is  the  most  important  industry.  Such  a  region 
is  a  good  illustration  of  a  middle-aged  region,  in  which 
the  river  forces  have  accomplished  a  great  many  changes 
since  the  land  was  first  built  into  a  plateau,  but  where 
there  is  still  a  great  quantity  of  work  to  be  done  before 
the  plateau  is  worn  down  level,  or  nearly  level,  present- 
ing the  features  of  an  old  region. 


CHAPTER   XIII. 

MOUNTAINS. 

IN  some  ways  the  most  interesting  of  the  greater  forms 
of  the  land  are  mountains.  Though  a  mountain  is  usually 
considered  as  a  peak  of  land  rising  to  a  high  level  above 
the  sea,  we  have  already  seen  that  single  mountains  are 
rare,  and  that  individual  peaks 'are  usually  but  points  in 
a  mountain  range.  Great  mountain  ranges,  like  the 
Appalachians  or  the  Cordilleras  of  this  country,  the  Alps 
in  Europe,  the  Himalayas  in  Asia,  are  extensive  high- 
lands, many  times  as  long  as  they  are  wide,  extending 
across  the  country  as  a  great  barrier  to  ready  travel,  and 
rising  to  varying  heights  in  the  different  regions.  In- 
deed, mountains  are  sometimes  considered  the  only  form 
of  highland ;  but  many  of  the  plateaus  of  the  world,  as, 
for  instance,  in  our  own  Western  region,  are  in  reality 
highlands,  rising  as  they  do  perhaps  a  mile  and  a  half 
above  the  level  of  the  sea.  The  form  and  shape  of  such 
areas  prove  them  not  to  be  mountains,  in  spite  of  their 
altitude. 

Mountains  stand  at  a  height  because  they  are  com- 
posed of  strong  rocks  which  the  erosive  forces  of  air, 
water,  and  ice  have  not  yet  been  able  to  wear  down. 
We  thus  find  that  mountain  masses,  as  a  rule,  are  the 
sources  of  rivers,  and  that  the  slope  of  the  valleys  cut 
into  the  mountains  is  steep.  This  steepness  of  slope, 
accompanied,  perhaps,  by  the  narrowness  of  the  valleys, 
makes  the  building  of  footpaths,  railroads,  or  roads  across 


MOUNTAINS. 


145 


mountains  a  difficult  and  an  expensive  matter,  so  that 
most  mountain  barriers  are  crossed  by  roads  or  railroads 
at  but  few  places,  and  then  at  the  pass  between  the 
higher  peaks.  (See  Fig.  69.)  The  steep  slopes  of  the 
mountains  in  the  lower  portions  are  usually  occupied  by 
forests ;  as  we  ascend  higher  and  higher  the  trees  grow 
smaller,  until  on  the  high  mountains  in  our  own  tem- 


FIG.    69. — A   MOUNTAIN   PASS    IN    IRELAND,    SHOWING    BORDERING   PEAKS 

OF    RANGE. 

perate  region  we  may  rise  above  the  line  where  trees  can 
grow,  into  the  region  occupied  only  by  lichens  and 
mosses,  or  perhaps  to  the  region  of  perpetual  snow.  In 
the  frigid  belts,  mountains  are  covered  by  snow  to  the 
very  sea  level ;  but  in  the  tropical  regions,  as,  for  instance, 
in  the  Himalayas,  snow  is  not  found  on  the  mountains 
except  above  a  height  of  about  20,000  feet. 

The  line  above  which  snow  remains  the  year  round  is 

10 


146  A   READER  IN   PHYSICAL  GEOGRAPHY. 

known  as  the  snow  line,  and  but  a  little  below  the  snow 
line  is  found  the  tree  line,  the  region  between  being  oc- 
cupied in  the  summer  by  the  lowly  forms  of  plants  noted 
above.  (See  Fig.  70.)  The  strong  rocks  of  which  moun- 
tains are  made  are  very  frequently  full  of  rich  and  valu- 
able minerals  and  ores,  so  that  the  one  great  industry 


FIG.    70. — A    MOUNTAIN     IN     BRITISH     COLUMBIA,     SHOWING     SNOW     LINE 
AND    TREE   LINE. 

associated  with  mountains  is  that  of  mining.  Except 
where  people  have  been  attracted  to  mountains  for  their 
mines  or  timber,  or  because  of  their  healthfulness  or 
beautiful  scenery,  we  find  mountainous  regions  but  little 
occupied.  (See  Fig.  71.)  We  think  of  them,  therefore,  as 
regions  of  wildness,  given  over  to  forests  and  wild  animals, 
such  as  bears,  wildcats,  Rocky  Mountain  goats,  etc. 


MOUNTAIN   BUILDING.  147 

Mountain  Building. — The  rocks  that  make  mountains 
have  in  some  way  been  heaved  or  crumpled  into  great 
folds  or  ridges,  the  individual  layers  not  lying  in  a  gen- 
erally flat  position,  as  in  plains  or  plateaus,  but  crumpled 
and  contorted,  and  perhaps  almost  on  edge.  This  crump- 


Fir,.  71. — A  PROMINENT  MOUNTAIN  PEAK  IN  CONNECTICUT,  SHOWING 
TILLED  FIELDS  AT  BASE,  WOODED  STEEPER  SLOPES,  AND  SUMMIT 
WITH  A  LOOKOUT  TOWER. 

ling  or  folding  of  the  rocks  of  a  mountain  range,  so  that 
they  do  not  spread  over  as  wide  an  area  as  formerly,  is 
what  determines  whether  a  region  is  mountainous  or  not. 
We  may  thus  have  mountains  of  low  altitude,  as  we  can 
have  plains  or  plateaus  of  high  altitude.  The  idea  of 
mountain  building  involves  not  only  elevation,  but  tilting 
or  folding  of  the  rocks  as  well.  (See  Fig.  72.)  Any 


148 


A   READER   IN   PHYSICAL   GEOGRAPHY. 


cause,  therefore,  that  will  tip  or  crumple  the  rocks  of  the 
earth,  is  a  mountain-building  force.  The  rocks  exposed 
on  Morningside  or  Washington  Heights  in  New  York 
City,  or  in  the  complicated  folds  to  be  seen  in  many 
places  in  the  Borough  of  the  Bronx,  have  been  mountain 


FIG.    72.— A   SMALL   MOUNTAIN   FOLD   AT   CATSKILL,    NEW   YORK. 

built,  and  present  to  us  beautiful  illustrations  of  small- 
scale  mountains. 

Causes  of  Mountains. — We  frequently  see  the  state- 
ment that  the  rocks  of  certain  parts  of  the  earth's  surface 
have  been  crumpled  into  great  folds  in  order  that  the 
surface  rocks  may  fit  the  interior  mass  of  the  earth, 
which  has  been  growing  smaller  as  it  has  cooled  from 


KINDS   OF   MOUNTAINS.  149 

a  previous  very  hot  condition,  just  as  the  thick  skin  of 
a  baked  apple  shrivels  and  crinkles  as  the  apple  cools. 
This  to  a  certain  extent  is  true;  but  it  is  not  the  only 
cause  of  mountain  building. 

Indeed,  the  causes  of  mountains  are  probably  so  nu- 
merous, and  are  so  complicated,  that  no  one  knows  them 
all.  We  must  therefore  acknowledge  the  difficulty  of 
explaining  mountains,  and  accept  them  as  the  results  of 
forces  beyond  our  present  understanding.  Perhaps  one 
more  suggestion,  however,  may  be  given  here.  Some- 
times it  happens  that  when  a  great  quantity  of  gravel  and 
rock  is  built  out  in  a  long  railroad  bed  on  the  muds  of  a 
flat  marsh,  the  marsh  will  rise  in  folds  on  the  two  sides 
of  the  roadbed,  as  recently  happened  in  Pelham,  New 
York.  The  mountain  building  in  such  a  case  is  due  to 
the  weighting  down  of  the  marsh  materials  in  one  spot, 
which  are  thus  squeezed  sideways  until  finally  they  buckle 
into  folds.  In  a  similar  way,  it  is  supposed  that  -the 
continued  removal  of  materials  from  the  surface  of  the 
land  to  the  shore  parts  of  the  ocean  causes  a  down- 
weighting  on  the  sea  floor  that  makes  the  adjacent  rocks 
of  the  land  crumple  into  mountains,  whose  general  direc- 
tion will  be  nearly  parallel  to  the  old  continent. 

Kinds  of  Mountains. — Mountains  are  most  frequently 
folded  into  long,  parallel  ridges,  as  a  series  of  sheets  of 
tissue  paper  would  be  crumpled  into  folds  if  one  edge 
were  held  firm  and  the  other  edge  pushed.  Such  linear 
or  folded  mountains  are  well  illustrated  in  the  Appala- 
chians, where  the  ridges  are  repeated  one  after  another, 
each  running  in  the  same  general  direction,  with  valleys 
between,  which  have  recently  been  formed  in  the  weak 
rocks.  Sometimes  the  mountain  masses  are  raised  into 
a  dome  from  the  pushing  from  beneath,  very  much  as 


ISO  A   READER  IN   PHYSICAL   GEOGRAPHY. 

the  bottom  of  a  tin  pan  will  rise  into  a  dome  if  pushed 
upward.  Then  the  layers  of  rocks  will  slope  away  in 
all  directions  from  the  centre.  Such  domed  mountains 
are  particularly  well  illustrated  in  the  Black  Hills  of 
Dakota  and  in  certain  other  regions  of  the  West. 
Occasionally  a  great  series  of  stratified  or  layered  locks 
have  been  broken  and  tipped  on  edge,  so  that  the  edges 
of  the  blocks  stand  up  in  steep  slopes,  with  the  original 
surface  sloping  away  in  the  opposite  direction.  We  can 
see  such  block  mountain  topography  illustrated  in  a  sim- 
ple way  when  the  ice  in  a  river  or  lake  becomes  broken, 
the  blocks  of  ice  tipping  in  several  directions,  and  per- 
haps freezing  together  again  in  their  new  positions,  mak- 
ing a  very  irregular  or  hummocky  surface,  difficult  to 
cross. 

It  is  easy  to  see  that  one  series  of  resistant  layers, 
tilted  and  broken  in  such  a  way,  may  make  many  moun- 
tain ranges,  varying  with  the  number  of  blocks  into  which 
the  original  mass  is  broken.  Certain  of  the  mountains 
of  Washington  and  Oregon,  and  certain  of  the  elevated 
peaks  of  the  Connecticut  Valley,  have  been  formed  in 
this  way.  Whatever  the  class  of  mountains,  the  result 
is  the  same: — an  elevation  of  rocks,  with  a  tilting  or 
crumpling  of  the  layers,  that  raises  a  large  amount  of 
material  to  a  sufficient  height  to  allow  river  valleys  to  be 
cut  into  it. 

Aging  of  Mountains. — Mountains,  as  well  as  plains 
and  plateaus,  grow  more  irregular  as  the  rivers  develop, 
and  a  young  mountain  range  would  be  one  in  which  the 
original  form  was  but  very  little  changed  through  the 
subsequent  cutting  of  river  valleys.  This  type  is  per- 
haps best  shown  in  the  block  mountains  of  Oregon. 
With  increased  aging  the  mountains  become  more  cut 


AGING   OF   MOUNTAINS.  15 1 

up,  more  irregular,  more  divided  into  peaks,  ridges, 
ravines,  and  valleys,  and  thus  more  beautiful.  In  such 
dissected  mountains,  people  may  live  in  the  different  val- 
leys, as  in  the  case  in  the  Swiss  Alps,  each  valley  com- 
munity almost  as  separate  and  distant  from  its  neighbors 
as  though  divided  by  miles  of  water  instead  of  perhaps 
by  a  single  ridge.  As  the  mountains  grow  still  older,  they 
will  of  course  be  worn  down  lower  and  lower,  until  they 
may  appear  as  a  lowland,  more  or  less  like  a  plain.  The 
fact  that  the  rocks  of  such  a  region  are  twisted  and  folded 
and  deeply  weathered  on  the  exposed  surface  testifies 
that  the  region  was  once  mountainous,  though  not  now 
showing  many  signs  of  mountain  topography.  Such  an 
old  mountain  lowland  is  well  shown  in  this  country  in 
the  so-called  Piedmont  (foot  of  the  mountains)  region  of 
Virginia,  lying  between  the  higher  ranges  of  the  Blue 
Ridge,  as  that  portion  of  the  Appalachians  is  called,  and 
the  low-lying  eastern  Coastal  Plain.  In  this  Piedmont 
region  the  old  mountains  have  not  been  worn  absolutely 
flat,  but  nearly  so.  Here  and  there  peaks  rise  to  a  mod- 
erate height,  showing  where  the  old  mountain  rocks  were 
strongest  and  most  resistant,  or  where  for  some  other 
reason  the  erosive  processes  have  not  been  able  to  do  all 
their  work. 

Such  lowlands,  formed  by  the  erosion  of  old  land  masses, 
are  sometimes  called  peneplains,  because  they  are  almost 
plains.  (See  Fig.  73.)  Since  they  have  been  made,  how- 
ever, they  may  have  been  raised  to  a  greater  height,  so 
that  the  even  line  which  marks  the  level  of  the  plain  may 
be  visible  only  to  one  who  climbs  out  of  the  recent  val- 
leys to  the  tops  of  the  ridges,  and  thereby  stands  upon 
the  elevated  lowland,  now  being  eroded  and  dissected 
again.  In  southern  New  Hampshire  is  a  fine  illustration 


152  A  READER   IN   PHYSICAL   GEOGRAPHY. 

of  such  a  peneplain,  above  which  certain  peaks  rise 
majestically,  of  which  Mount  Monadnock  is  a  noble  ex- 
ample. Hence  those  points  which  have  never  been  worn 
to  the  lowland  level  are  sometimes  called  monadnocks. 
We  need  not,  however,  go  to  New  Hampshire  to  find  such 
a  peneplain,  made  in  old  mountain  rocks,  for  New  Jersey 
shows  the  same  features  most  beautifully.  One  standing 


FIG.    73. — A    BIT    OF    A    PENEPLAIN    IN  CONNECTICUT,    SHOWING   STEEP- 
SIDED    YOUNG    VALLEY    CUT    BELOW    LEVEL   OF   UPLAND. 

on  the  edge  of  the  Orange  or  Watchung  Mountains  in 
Montclair  or  Orange,  New  Jersey,  sees  all  the  ridges  about 
him  at  approximately  the  same  level,  marking  the  old 
peneplain.  Below  him  are  the  valleys  cut  in  recent 
times,  and  far  away  to  the  northwest  may  be  seen  occa- 
sional small  monadnocks  rising  a  few  hundred  feet  above 
the  even  sky-line  of  the  peneplain. 

Thus  as  mountains  grow  older  and  lower,  their  majesty 
and  variety  of  topography  disappear,  and  plants,  animals, 


AGING  OF  MOUNTAINS.  153 

and  men  no  longer  find  in  the  mountains,  regions  that 
cannot  be  occupied  because  they  are  too  high  and  too 
hard  to  reach.  The  region  can  be  used,  perhaps,  for 
agriculture  and  other  occupations.  If  the  original  moun- 
tains contained  minerals  of  value,  man  has  lost  so  much 
possible  wealth  through  the  wearing  away  of  the  rocks 
and  the  removal  of  the  minerals  bit  by  bit  to  the  ocean. 
Men  living  in  the  river  valleys  near  mountains  that  are 
now  wearing  away  and  sending  down  to  the  rivers  bits  of 
gold  with  the  gravel  and  sand,  often  wash  the  gravels 
and  catch  and  save  the  specks  of  gold ;  this  form  of 
mining  is  known  as  placer  mining. 


CHAPTER    XIV. 

VOLCANOES. 

VOLCANOES  make  up  the  fourth  and  last  of  the  several 
great  groups  of  land  forms  that  we  have  to  consider. 
Volcanoes  are  not  as  important  or  as  numerous  in  the 
world  as  are  the  plains,  plateaus,  and  mountains.  They 
are,  however,  extremely  interesting,  and  are  full  of  won- 
derment to  most  people  because  of  the  awe  associated 
with  them.  A  volcano  is  essentially  an  opening  in  the 
earth  from  which  the  pent-up  energy  of  the  interior 
escapes  as  steam,  very  much  as  steam  escapes  from  an 
engine  when  the  pressure  gets  too  high.  As  the  heat 
and  water  making  the  steam  come  from  a  great  depth  in 
the  earth,  the  crack  or  opening  by  means  of  which  they 
reach  the  surface  must  extend  many  thousands  of  feet 
down  into  the  earth.  The  escaping  steam  frequently,  and 
indeed  usually,  melts  the  rocks  through  which  it  comes, 
making  them  sufficiently  liquid  to  boil  to  the  surface 
almost  as  easily  as  the  water.  Thus  in  most  volcanic 
eruptions  we  have,  besides  the  ever-present  steam,  the 
pouring  forth  of  an  enormous  quantity  of  rock,  in  a  liquid 
form,  known  as  lava. 

If  the  energy  of  a  volcano  is  very  severe,  the  steam 
penetrating  through  the  liquid  lava  blows  it  into  bubbles, 
very  much  as  a  small  boy  blows  soapy  water  into  bub- 
bles ;  the  lava  may  then  come  forth  upon  the  surface  of 
the  earth,  and  afterwards  cool  into  a  mass  of  rock  full  of 


VOLCANOES.  155 

rounded  holes,  just  as  cheese  or  bread  Is  sometimes  full 
of  gas  or  steam  holes.  When  the  holes  are  small  and 
very  numerous,  the  rock  is  called  pumice-stone.  If  the 
energy  is  sufficient  to  have  the  bubbles  burst,  then  the 
rock  materials  that  formed  the  surface  of  the  bubbles  are 
blown  into  very  fine  dust-like  particles,  known  as  "  ashes," 
or  "cinders."  This  again  is  sometimes  illustrated  in  the 
blowing  of  soap  bubbles  when  the  bubble  bursts,  and 
the  thin  film  of  water  that  formed  the  surface  of  the  bub- 
ble spatters  into  the  blower's  face  as  several  small  drops 
of  water.  As  a  matter  of  fact,  there  is  no  burning  of  the 
rocks  in  a  volcanic  eruption,  and  hence  there  can  be  no 
real  ashes.  The  material  is  spoken  of  as  "  ashes  "  because 
it  is  so  fine  and  ash-like  in  its  appearance. 

Any  eruption  beginning  in  a  severe  way  may  blow  the 
ashes  into  the  air  to  a  tremendous  height,  so  that  they 
are  wafted  by  the  winds  far  and  wide,  perhaps  forming 
a  cloud  that  makes  the  day  dark,  and  which  may  cover 
everything  with  a  thick  layer  of  dust  as  they  fall.  The 
famous,  eruption  of  Vesuvius  in  the  year  79,  when  the 
ashes  and  lava  buried  two  cities,  Herculaneum  and  Pom- 
peii, was  of  this  character.  A  very  great  series  of  violent 
eruptions  occurred  during  the  summer  of  1902,  in  the 
islands  of  Martinique  and  St.  Vincent,  in  the  Lesser 
Antilles.  These  eruptions  caused  an  enormous  loss  of 
life  and  property,  and  were  the  most  destructive  eruptions 
ever  known.  Great  clouds  of  ashes  and  steam  hung  over 
the  islands,  and  the  dust  fell  upon  vessels  several  hundred 
miles  away.  (See  Fig.  74.)  No  liquid  rock,  or  lava,  was 
poured  forth,  however,  in  the  several  very  violent  erup- 
tions which  occurred  between  May  8  and  August  30, 
1902. 

During  the  latter  part  of  an  eruption,  when  the  energy 


156  A   READER   IN   PHYSICAL   GEOGRAPHY. 


has  decreased,  the  lava  may  pour  forth,  and  flow  down 
over  the  neighboring  country.  After  the  lava  has  ceased 
to  appear  at  the  surface,  the  steam  may  continue  to 
escape  from  the  volcanic  opening  under  the  earth  for  a 
long  time,  and  the  lava  may  be  heard  or  felt  boiling  or 
rumbling  in  the  depths  below.  Indeed,  some  volcanoes 


— — ^— — — ^ — — — ^^^^^^=^^=^^^^= 

By  courtesy  of  American  Museum  of  Natural  History. 

FIG.    74. — MONT    PELEE    IN    ERUPTION. 

are  continually  rumbling  and  steaming,  but  burst  forth  in 
an  eruption  only  at  very  long  intervals. 

Shape  of  Volcanoes. — The  solid  material  poured  out 
in  either  of  the  forms  mentioned  may  accumulate  near 
the  volcanic  opening,  and  gradually  build  up  a  great 
heap  of  materials,  until  we  have  a  great  conical  elevation 
of  land,  known  as  a  volcano.  Volcanoes  are  sometimes 


SHAPE   OF   VOLCANOES. 


157 


spoken  of  as  mountains,  because  of  their  height ;  but  they 
are  not  mountains,  as  there  is  not  necessarily  any  upfold- 
ing  of  the  rock  layers  such  as  we  find  in  mountains.  The 
conical  shape  is  common  to  most  of  the  well-known  vol- 
canoes of  the  world,  of  which  the  two  best  examples  are 
perhaps  the  famous  Vesuvius,  in  Italy,  and  the  still  more 
beautiful  and  symmetrical  Fuji-yama,  in  Japan.  A  vol- 
canic cone  has  at  its  top  a  cup-like  depression  known  as 


FIG.  75. — SMALL  AND  VERY  SYMMETRICAL  VOLCANIC  CONE  IN  OREGON. 

the  crater,  in  the  centre  of  which  is  the  opening  known 
as  the  throat.  The  throat,  the  crater,  and  the  cone  are 
common  features  of  all  volcanoes,  though  the  features  of 
each  may  differ  in  different  volcanoes.  (See  Fig.  75.)  Each 
time  that  there  is  an  eruption  of  lava,  the  moving  flood 
of  rock  flows  down  depressions  in  the  sides  of  the  vol- 
cano like  water,  seeking  the  lowest  level.  If  the  erup- 
tions are  a  sufficiently  long  time  apart  to  allow  the  cutting 
pf  river  valleys  into  the  volcano,  the  next  eruption  will 


158  A   READER   IN   PHYSICAL  GEOGRAPHY. 

probably  more  or  less  fill  the  depressions,  thereby  renew- 
ing the  symmetrical  conical  shape  of  the  volcano.  By 
studying  the  relations  of  the  different  flows  of  rock  to  one 
another,  it  is  possible  sometimes  to  work  out  the  order 
of  their  appearance,  and  to  get  something  of  the  story  of 
the  upbuilding  of  the  cone  as  a  whole. 

Kinds  of  Volcanoes. — There  are  two  classes  of  vol- 
canoes ;  one  that  is  high  and  narrow,  and  the  other  low  and 
broad.  Vesuvius  is  a  good  illustration  of  the  first  class  of 
volcanoes,  for  it  has  a  steep  cone  and  a  small  cup-like  crater 
at  the  top.  By  far  the  larger  number  of  the  great  vol- 
canoes of  the  world  belong  to  this  class.  In  some  cases, 
however,  volcanic  peaks  occur  as  caps  on  the  top  of 
mountain  ranges,  so  that  the  full  height  and  size  of  the 
peaks  are  not  due  entirely  to  volcanic  action.  Such,  for 
instance,  are  some  of  the  famous  volcanoes  of  South 
America,  like  Cotopaxi  and  Chimborazo. 

The  second  great  group  of  volcanoes  has  a  low,  flat 
cone,  with  a  broad,  saucer-like  crater  in  which  the  lava 
may  stand  sometimes  as  a  great  lake,  for  years,  slowly 
rising  and  falling,  until  it  finally  overflows,  allowing  the 
lava  to  escape  to  lower  regions.  Such  are  most  of  the 
volcanoes  of  the  Hawaiian  Islands.  Owing  to  the  size 
and  shape  of  the  crater,  there  is  not  so  great  an  oppor- 
tunity for  the  energy  to  be  held  in,  in  this  group  of  vol- 
canoes, as  in  the  first  class,  and  hence  the  eruptions  are 
likely  to  be  more  quiet  and  less  renowned. 

Sometimes  we  have  evidences  that  great  volcanic  out- 
bursts have  occurred  in  different  parts  of  the  world,  not 
apparently  from  any  single  cone  or  crater,  but  perhaps 
from  a  group  of  craters,  or  possibly  from  a  series  of  great 
cracks  under  the  earth,  from  which  the  lava  has  poured 
forth  in  tremendous  volumes.  In  our  own  great  West, 


AGING   OF  VOLCANOES. 


159 


as  is. well  illustrated  in  Oregon  and  Idaho,  we  have  thou- 
sands of  square  miles  of  country  covered  by  an  unknown 
depth  of  lava,  which  apparently  poured  forth  in  some 
such  way.  There  are  also  extensive  lava  fields  in  Arizona. 
(See  Fig.  76.)  The  lava,  like  water,  filled  all  the  depres- 
sions in  the  land  to  a  level,  and  then  froze  permanently 
into  solid  rock,  so  that  we  now  have  a  great  lava  plain 
made  up  entirely  of  such  frozen  lava,  and  resembling, 


FIG.    76. — A    VOLCANIC    CINDER    CONE    AND    LAVA    FIELD    IN    NORTHERN 

ARIZONA. 

both  in  manner  of  origin    and  in  shape,  the  winter  ice 
plains  made  by  the  temporary  freezing  of  water  in  lakes. 

Aging  of  Volcanoes. — Many  of  the  volcanoes  of  the 
world  are  no  longer  active,  but  are  in  various  stages 
of  aging,  depending  upon  the  amount  of  weathering  that 
has  taken  place  since  they  became  inactive.  The  inactive 
volcanoes  that  are  the  most  youthful  in  their  topography 
are  those  where  activity  has  just  ceased,  and  where  the 
lava  filling  the  throat  of  the  volcano  has  become  frozen 
as  a  solid  plug,  bearing  the  same  relation  to  the  volcano 


l6o  A   READER   IN   PHYSICAL   GEOGRAPHY. 

that  a  cork  does  to  a  bottle.  In  such  cases  the  crater  no 
longer  has  an  opening  in  the  bottom,  but,  like  a  wash- 
basin, is  capable  of  holding  water.  As  a  result,  the  rain- 
fall accumulates  in  the  crater  depression,  forming  a  lake, 
which  may  rise  until  the  water  can  flow  out  at  the  lowest 
point  of  the  edge.  In  the  centre  of  France  there  are 
many  such  instances  of  inactive  volcanoes,  each  with  its 
crater  lake  in  its  summit.  Such  volcanoes  must,  of 


FIG.   77. — PANORAMA   OF    CRATER    LAKE,    OREGON,    INCLUDING   WIZARD 

ISLAND. 

course,  be  very  young,  because  if  a  long  time  had  elapsed 
since  they  last  were  active,  the  rim  of  the  crater  would 
have  been  more  or  less  worn  away,  so  that  the  water 
could  escape. 

In  Oregon  we  have  a  famous  Crater  Lake,  not  quite 
similar  to  those  in  France,  but  still  a  lake,  lying  in  the 
summit  of  an  ancient  volcano.  (See  Fig.  77.)  In  this 
case,  however,  the  top  of  the  original  volcano  has  disap- 
peared, and  we  now  have  a  great  depression,  with  cliff- 
like  walls  many  hundred  feet  in  height.  Since  that  time  a 
small  new  cone  has  grown  up  within  the  great  depression, 


AGING   OF   VOLCANOES. 


161 


and  thus  we  have  one  cone  within  another.  This  small 
cone  forms  an  island,  known  as  Wizard  Island.  In  the 
course  of  time,  however,  as  the  volcano  grows  older, 
the  cliffs  will  be  worn  down  and  the  water  of  the  lake 
will  thereby  be  drained  away. 

We  have  a  similar  condition  in  the  case  of  Vesuvius, 
where  the  present   cone  lies  in  the  centre  of  an  old  de- 


ne. 78. — ONE   EFFECT  OF  AN  EARTHQUAKE  IN   LOS  ANGELES, 
CALIFORNIA,    IN    1899. 

pression  which  is  bordered  on   all  sides  by  cliffs  which  are 
the  remains  of  the  top  of  the  old  cone. 

As  volcanoes  wear  away,  those  portions  which  are 
made  of  the  most  resistant  or  strongest  rocks  will  resist 
weathering  the  longest ;  hence  a  volcano  will  be  cut  into 
peaks,  ridges,  and  ravines,  very  similar  in  form  to  those  of 
domed  mountains,  the  ravines  heading  toward  the  centre 
of  the  volcano,  and  radiating  out  like  the  spokes  of  a 


l62  A   READER   IN   PHYSICAL   GEOGRAPHY. 

wheel,  as  is  illustrated  on  the  sides  of  the  ancient  and 
well-worn  volcano  of  Mount  Shasta,  in  California.  When 
volcanoes  have  been  worn  down  nearly  flat,  the  last  rem- 
nants, standing  as  elevations  above  the  eroded  land,  will, 
of  course,  be  where  the  strongest  rocks  occurred.  Usually 
the  solid  lava  .that  filled  the  throat  of  the  volcano  resists 


FIG.  79. — AN    ERUPTION    OF    THE    GIANT,    THE     LARGEST     GEYSER     IN 
YELLOWSTONE    PARK. 

weathering  the  longest,  so  that  the  last  sign  of  a  volcano 
in  a  region,  at  least  as  shown  in  the  topography,  is  the 
presence  of  a  neck  as  a  conspicuous  landmark  in  the  plain. 
Such  necks  are  the  worn-out  stumps  of  ancient  volcanoes, 
and  are  sure  signs  of  the  former  presence  of  a  great 
cone  that  has  been  worn  away.  In  certain  parts  of 
Arizona  and  New  Mexico  there  are  beautiful  illustra- 
tions of  such  old  volcanoes,  rising  conspicuously  above 


EARTHQUAKES.  163 

the  old  plain  down  to  which  the  rest  of  the  region  has 
been  worn. 

Earthquakes. — Associated  with  any  great  volcanic 
eruption  there  is  always  a  series  of  earth  tremblings, 
known  as  earthquakes.  Such  quakings  are  due  to  a  blow 
given  in  some  way  to  the  rocks  in  the  interior  of  the 
earth,  so  that  they  vibrate  as  a  bell  vibrates  when  struck 


FIG.  8O — A    GEYSER   CONE    AND    FIELD    IN    YELLOWSTONE    PARK. 

by  the  hammer.  Sometimes  the  earthquakes  are  suffi- 
ciently strong  to  shake  down  houses,  and  to  cause  other 
injuries  to  man's  property.  (See  Fig.  78.)  All  earth- 
quakes are  due  either  to  volcanic  explosions  or  to  move- 
ments in  the  rocks  due  to  mountain  building  going  on 
beneath  the  surface  of  the  earth.  The  oncoming  of  an 
eruption  in  a  volcano  may  often  be  foretold  by  an  increase 
in  the  frequency,  and  perhaps  in  the  strength,  of  the 
earthquakes  in  the  neighboring  region.  Indeed,  volcanic 


164  A   READER   IN   PHYSICAL   GEOGRAPHY. 

countries  like  Iceland  and  Japan  are  famous  earthquake 
regions.  Certain  parts  of  Japan  are  shaken  every  year 
by  several  hundred  earthquakes  of  sufficient  strength  to 
be  felt,  if  not  by  men  and  animals,  at  least  by  delicate 
instruments  that  have  been  made  to  measure  and  record 
such  earth  movements.  The  greater  part  of  the  world  is, 
however,  free  from  frequent  or  severe  earthquake  shocks, 
and  most  of  the  people  in  the  United  States  have  never 
experienced  any  severe  earthquakes. 

Geysers  and  Hot  Springs. — Volcanoes  are  not  the 
only  forms,  however,  which  are  made  from  materials 
brought  from  within  the  earth  by  hot  water.  Sometimes 
the  heated  waters  that  rise  to  the  surface  as  hot  springs 
bring  with  them  in  solution  a  certain  quantity  of  mineral 
matter,  which,  crystallizing  as  the  water  cools,  accumulates 
as  deposits  around  the  spring,  just  as -sugar  solidifies  from 
a  syrup  when  it  is  cooled.  A  similar  accumulation  may 
take  place,  often  to  a  considerable  depth,  around  those 
intermittent  or  spouting  hot  springs  that  are  known  as 
geysers  (see  Fig.  79),  of  which  the  best  and  most  numer- 
ous examples  are  found  in  the  Yellowstone  National 
Park.  There  the  geyser  and  hot-spring  deposits  cover 
a  large  area,  and  are  in  certain  places  of  great  depth. 
(See  Fig.  80.)  The  geyser  and  hot-spring  cones  have 
many  features  similar  to  those  of  volcanoes,  particularly 
in  shape,  although,  of  course,  they  are  smaller  in  size. 
Hot  springs,  geysers,  and  volcanoes  are  but  different 
illustrations  of  the  activity  of  heat  from  within  the 
earth,  the  heat  of  hot  springs  and  geysers,  however,  being 
less  intense  than  that  of  volcanoes,  and  their  eruptions 
less  striking  and  awful. 


CHAPTER    XV. 

MOVEMENTS   OF   THE    LAND. 

WE  have  already  seen  some  of  the  effects  of  the  slow 
upbuilding  of  mountain  ranges,  and  the  slow  rising  of  the 
coastal  parts  of  the  land,  whereby  the  bottom  of  the 
ocean  may  become  revealed  as  a  coastal  plain  bordering 
the  water.  Movements  of  the  continent,  or  of  parts  of 
the  continent,  are  very  slow,  but  continuous,  as  is  indi- 
cated by  the  frequent  earthquakes  in  regions  which  are 
not  volcanic,  and  where,  therefore,  the  tremblings  must 
be  due  to  mountain  building.  After  a  long  period 
of  time,  however,  the  effects  of  these  movements  may  be 
seen  in  some  of  the  new  conditions  which  they  bring 
about. 

It  is  very  rarely  that  any  man  can  see  in  the  course  of 
his  life  any  movement  sufficiently  great  to  make  any 
change  in  the  features  about  him ;  but  yet  he  can  be  sure 
that  such  movements  are  taking  place  by  studying  some 
of  the  features  about  him  that  evidently  could  not  have 
been  made  with  the  land  in  its  present  position  in  refer- 
ence to  the  ocean.  For  instance,  in  Norway  there  is  a 
great  cave  on  the  coast  facing  the  ocean,  but  now  several 
hundred  feet  above  sea  level.  In  that  cave  are  the 
rounded,  water-worn  pebbles  that  show  by  their  shape 
how  they  were  formed :  they  testify  to  former  water 
work  in  the  cave,  and,  indeed,  they  were  the  tools  that 
the  water  used  in  cutting  the  cave.  As  the  cave  could 


1 66  A   READER   IN   PHYSICAL   GEOGRAPHY. 

i 

not  have  been  cut  in  its  present  position,  the  story  it 
tells  is  clearly  to  the  effect  that  the  region  has  risen  in 
very  recent  times.  There  are  many  other  similar  in- 
stances in  various  parts  of  the  world  that  prove  without 
any  doubt  the  recent  movements  of  the  land. 

Of  course  the  movement  may  be  upward,  so  that  the 
land  is  raised  above  the  ocean,  causing  perhaps  a  large 
area  of  ocean  floor  to  be  added  to  the  continent ;  or  the 
movement  may  be  downward,  so  that  the  water  of  the 
sea  advances  over  and  covers  parts  of  the  land. 

Coast  Lines. — The  first  sign  of  such  a  change  in  the 
relative  position  of  the  land  and  ocean  is  the  new  coast 
line,  the  new  meeting  place  of  land  and  water.  If  the 
movement  has  been  upward,  the  former  coast  line  will 
thus  be  raised  and  carried  away  from  the  ocean,  so  that 
it  appears  on  the  sides  of  the  hills,  but  with  every  feature 
retained.  Indeed,  the  features  may  be  so  carefully  pre- 
served, and  so  striking,  that  one  standing  on  the  old  sea 
beaches  or  capes,  with  his  back  to  the  distant  ocean, 
might  easily  imagine  himself  on  a  'present  sea  beach  at 
low  tide. 

If  the  movement  is  downward,  the  water  naturally 
advances  upon  the  land,  fitting  into  all  the  irregularities 
of  the  land,  and  filling  up  the  hollows  to  a  common  level. 
The  more  irregular  the  land  surface  when  the  movement 
takes  place,  the  more  irregular  the  coast  line  that  will 
result.  Such  an  irregular  coast  line,  formed  in  this  way, 
is  commonly  spoken  of  as  that  of  a  drowned  region,  inas- 
much as  part  of  the  old  land  surface  has  been  carried 
below  the  water  level,  or,  as  we  may  rightly  say,  drowned. 
(See  Fig.  81.)  If  the  land  that  was  drowned  was  made 
of  rocks  of  varying  hardness,  and  much  cut  up  into  hills 
and  valleys,  the  shore  line  will  be  much  more  irregular 


COAST  LINES. 


I67 


than  if  the   region   had   been   one  of   relatively  uniform 
strength.     The  water,   rising   up  into  the  river  valleys, 


Longmans,  Green  &  Co.  Born*,  &  a>..  x.  r. 

FIG.  8 1. — MAP  OF  A  DROWNED  VALLEY  IN  MARYLAND.  NOTE  FORMATION 
OF  PENINSULAS,  IRREGULAR  CHARACTER  OF  COAST  LINE,  AND  POSI- 
TION OF  ROADS  AND  HOUSES. 

would  wash  the  shores  of  the  old  hills,  and  perhaps  cover 
some  of  them.     The  higher  peaks  would  remain  perhaps 


1 68 


A   READER   IN   PHYSICAL   GEOGRAPHY. 


above  water,  as  islands  or  peninsulas,  the  islands  in  line 
with  the  higher  peninsulas,  thus  indicating  the  direction 
of  the  drowned  ridge.  (See^Fig.  82.) 

It    is   largely  through    drowning   that    peninsulas  are 
made,  and  many  of  the  capes  of  the  world  are  on  the 


FIG.    82.— A   STRONG   ROCK    PENINSULA   AT   MARBLEHEAD,    MASSACHU- 
SETTS,   FORMED    BY    DROWNING. 


seaward  end  of  strong  rock  ridges,  most  of  which  have 
been  drowned.  A  slight  downward  movement  of  the 
land  in  reference  to  the  water  might  cause  the  point  of 
a  peninsula  to  become  an  island,  or  if  the  movement 
were  in  the  opposite  direction,  the  island  might  again  be 
joined  to  the  mainland,  and  be  added  to  the  promontory 
as  a  peninsula,  thus  lengthening  the  point. 


DROWNED   VALLEYS.  169 

Drowned  Valleys. — The  more  complete  the  drowning, 
the  fewer  ridges  whose  tops  would  project  above  the 
water,  and  hence  the  more  regular  the  coast  line.  In 
the  vicinity  of  New  York  the  drowning  has  allowed  the 
water  of  the  ocean  to  penetrate  for  miles  inland  along 
the  river  valleys,  as  in  the  cases  of  the  Hudson  and  Dela- 
ware rivers  and  in  Chesapeake  Bay.  This  makes  it  possi- 
ble for  ocean  vessels  to  go  directly  from  foreign  ports  to 
large  cities  which  are  actually,  as  in  the  case  of  Philadel- 
phia or  Baltimore,  a  long  distance  from  the  open  sea. 

How  are  we  to  know,  therefore,  that  a  given  valley  has 
been  drowned  ?  In  the  case  of  certain  parts  of  Chesa- 
peake Bay  it  is  very  easy  to  reproduce  in  one's  imagina- 
tion the  courses  of  the  old  rivers  and  their  tributaries 
that  ran  along  the  deepest  parts  of  the  present  bays  or 
estuaries.  (See  Fig.  81.)  We  can  see  from  the  map  that 
all  the  big  bays  point  toward  each  other  as  the  large 
rivers  point  toward  a  main  stream  •  that  all  the  small 
bays  point  toward  the  larger  bays,  and  that,  were  the 
water  to  be  drained  off,  the  rivers  that  now  mouth  at 
the  bays  would  continue  down  stream  until  they  formed 
a  river  system  again. 

It  is  another  matter,  however,  to  tell  that  such  a  river 
as  the  Hudson  has  been  drowned,  and  yet  it  is  not  diffi- 
cult. In  the  first  place,  tides  nearly  to  the  source  of  the 
river  suggest  deep  and  quiet  water,  and,  of  course,  a  level 
very  close  to  that  of  the  ocean.  Then,  again,  the  amount 
of  water  in  the  Hudson  at  any  one  time  is  very  large,  and 
the  area  from  which  the  Hudson  receives  drainage  is  alto- 
gether too  small  to  supply  it  all.  Therefore  there  must 
be  some  other  water  than  rain  water  in  the  river,  and  as 
the  water  is  salt,  it  must  be  ocean  water.  This  of  course 
means  a  depression  that  has  allowed  the  ocean  water  to 


170  A   READER   IN   PHYSICAL  GEOGRAPHY. 

come  in,  for  rivers  cannot  cut  down  the  channel  of  their 
whole  course  below  the  level  of  the  sea.  The  drowned 
Hudson  River,  and  the  adjacent  East  and  Harlem  rivers, 
have  given  splendid  opportunity  for  commerce,  and  the 
hilltops  that  were  never  completely  drowned,  but  which 
rise  in  Manhattan  Island,  Long  Island,  and  Staten  Island, 
are  but  the  undrowned  hilltops  of  a  former  extensive  land 
surface  that  offer  a  chance  for  the  position  of  large  cities. 
Were  the  land  in  this  region  to  rise  again,  so  that  the 
water  of  the  ocean  were  drained  off  to  the  extent  it  once 
was,  Manhattan  Island  would  be  but  a  hilltop,  seventy- 
five  miles  inland,  in  every  way  similar  to  hilltops  that 
appear  to-day  in  western  Massachusetts  and  Connecticut. 
We  have  already  suggested,  in  the  early  part  of  the 
book,  some  of  the  effects  of  such  drowned  shore  lines  in 
making  a  large  area  of  land  available  for  occupation,  and 
for  the  development  of  agriculture  and  commerce. 
Straight  and  regular  shore  lines,  formed  usually  by  the 
elevation  of  the  land,  so  that  the  waters  of  the  ocean 
wash  against  the  even  slope  of  the  newly  elevated  sea 
bottom,  making  a  coastal  plain,  have  but  few  breaks 
through  into  the  interior,  offer  few  chances  for  har- 
bors, and  give  but  few  people  ready  access  to  the  water; 
whereas  on  an  irregular,  or  bayed  shore,  many  people 
can  have  their  own  bit  of  shore  where  they  can  land  ves- 
sels, the  bays  giving  a  splendid  opportunity  for  protected 
harbors. 


CLIMATE. 

CHAPTER   XVI. 
WHAT    IS   WEATHER   AND   CLIMATE? 

PERHAPS  the  first  thought  that  comes  into  one's  mind 
when  we  ask  whether  a  certain  region  is  habitable  or  not, 
is  the  question  of  climate.  The  great  climatic  divisions 
of  the  world  mark  out  the  regions  in  which  men,  ani- 
mals, and  plants  can  live,  and  in  those  different  regions 
we  find  that  the  topography  has  much  to  do  in  deter- 
mining how  large  a  proportion,  and  what  parts,  may  be 
occupied  by  life  to  the  best  advantage.  In  considering 
the  climate,  therefore,  we  must  think  of  many  things 
that  belong  to  the  world  as  a  whole;  we  must  study 
that  world  so  that  we  can  divide  it,  according  to  its 
climate,  into  the  habitable  and  the  uninhabitable  regions. 

It  would  be  well  at  the  beginning  to  find  out  exactly 
what  we  mean  by  climate,  for  sometimes  we  speak  of 
a  dry  or  a  wet  climate,  a  cold  or  a  warm  climate,  an 
unhealthy  climate,  etc.  Does  this  mean  one  and  the 
same  thing,  or  is  climate  really  a  very  complicated  mat- 
ter, made  up  of  a  number  of  different  features? 

In  speaking  of  the  climate  of  a  region,  we  of  course  think 
of  the  conditions  of  the  air,  just  as  the  weather  any  day 
includes  all  those  atmospheric  conditions  that  affect  us. 
Indeed,  the  climate  is  but  the  average  of  these  weather 


172  A   READER   IN   PHYSICAL  GEOGRAPHY. 

conditions  by  seasons,  and  is  determined,  of  course,  by 
studying  the  weather  for  a  long  period  of  time,  and  find- 
ing out  what  features  of  the  weather  are  most  common 
and  may  be  expected  most  frequently  in  any  particular 
region.  As  climate,  therefore,  is  but  average  weather, 
we  had  best  first  see  what  it  really  is  we  familiarly  call 
the  weather. 

Weather  and  Climate. — When  one  person  remarks  to 
another  that  this  is  fine  weather,  he  probably  has  in  mind, 
first,  the  fact  that  the  day  is  clear,  rather  than  cloudy  or 
stormy,  so  that  the  kind  of  day  is  perhaps  the  first  point 
to  be  considered  as  a  part  of  weather;  in  a  similar  way,  in 
a  study  of  climate  the  average  character  of  days  in  the 
different  seasons,  whether  they  be  clear,  cloudy,  or  rainy, 
determines  the  general  climate;  for  regions  where  there 
are  many  clouds  and  much  rain  must  be  moist,  and  those 
where  it  is  generally  fair  must  be  more  or  less  dry. 

Next  to  the  kind  of  day  is  the  question  of  temperature ; 
that  is,  whether  the  day  be  cold,  cool,  warm,  or  hot. 
We  shall  find,  however,  that  sometimes  the  days  in  which 
the  temperature  is  the  highest  or  lowest  do  not  make  us 
feel  the  most  uncomfortable,  and  in  the  summer,  at  least, 
the  most  disagreeable  days  are  not  those  which  are  in 
reality  the  warmest,  although  we  may  think  from  our 
own  feelings  that  they  are  very  hot.  We  expect  cold 
days  in  the  winter  season  and  hot  days  in  the  summer 
season,  and  in  deciding  upon  the  climate  of  any  region 
we  have  to  take  into  account  the  general  temperature 
conditions  at  the  different  seasons.  In  the  same  way, 
in  deciding  upon  the  climate  of  any  part  of  the  world  we 
have  to  think  whether  the  temperature  during  the  year 
is  uniformly  cold,  or  hot,  or  variable.  Those  regions 
which  have  extremely  low  temperatures  in  the  winter, 


WEATHER  AND   CLIMATE.  173 

and  no  long-continued  warm  spells  during  the  year,  we 
speak  of  as  arctic  in  character,  and  as  having  an  arctic 
climate.  Those  that  are  extremely  warm  the  year  round, 
with  but  little  change  of  temperature  from  month  to 
month,  we  speak  of  as  being  tropical  in  their  nature. 

The  third  matter  that  has  to  be  considered  in  deter- 
mining the  climate,  or  weather,  of  a  region  is  something 
that  we  do  not  ordinarily  notice  from  our  own  feelings, 
and  that  is  the  weight  or  the  pressure  of  the  air.  And 
yet  this  is  a  very  important  matter,  because  it  is  a  differ- 
ence in  weight  of  the  air  in  neighboring  places  that  gives 
us  our  winds,  the  wind  being  air  in  motion  over  the  earth, 
from  where  there  is  a  great  deal  of  air  to  a  region  where 
there  is  less  air,  or  from  where  the  air  is  heavy  to  where 
it  is  light.  It  is  very  easy  to  show,  as,  for  instance,  by 
blowing  against  a  piece  of  paper,  that  air  has  weight  and 
can  give  a  push ;  but  it  is  hard  to  illustrate  changes  in 
that  weight  without  the  use  of  instruments.  We  can, 
however,  as  we  shall  see  under  the  study  of  the  winds, 
find  out  where  the  air  is  light  and  where  it.  is  heavy;  and 
if  we  find  that  in  any  parts  of  the  world  the  winds  are  in 
general  from  particular  directions,  we  know  at  once  that 
the  air  to  leeward  is  always  lighter  for  some  reason  than 
the  air  to  windward. 

Next  to  the  kind  of  day  and  the  temperature,  in  deter- 
mining whether  the  weather  is  agreeable  or  disagreeable, 
is  probably  the  question  of  the  wind.  A  windy  day, 
particularly  when  it  is  cold,  or  when  it  is  hot  and  dusty, 
is  one  of  the  most  disagreeable  of  days,  no  matter  what 
the  other  general  conditions.  A  country  in  which  the 
winds  are  prevailingly  strong  or  boisterous  has  a  dis- 
agreeable climate,  whether  it  be  cold  or  warm.  We 
should  probably  find  it  equally  disagreeable  to  live  in 


1/4  A   READER  IN   PHYSICAL   GEOGRAPHY. 

a  region  in  which  the  winds  were  very  light  and  infre- 
quent, and  where  we  were  not  cooled  by  the  blowing  of 
the  air  against  us. 

In  thinking  of  the  wind,  we  need  to  note  its  direc- 
tion ;  that  is,  the  point  of  the  compass  from  which  it 
is  blowing,  and  the  velocity  with  which  it  is  moving. 
A  wind  that  is  moving  over  the  ground  at  the  rate 
of  thirty  miles  an  hour,  as  fast  as  an  average  railroad 
train,  is  a  strong  wind,  and  generally  an  unpleasant  one. 
Wind  that  is  moving  at  the  rate  of  sixty  or  seventy  miles 
an  hour,  as  very  infrequently  happens  in  the  Eastern 
United  States,  is  a  gale,  destructive  in  its  violence,  and 
very  hard  to  withstand  if  one  must  face  it. 

The  next  point  that  has  to  be  considered  in  summing 
up  the  weather  is  the  question  of  the  amount  of  moisture 
in  the  air.  It  is  very  evident  that  when  it  rains  or  snows, 
or  when  there  is  a  fall  of  sleet  or  hail,  the  air  is  full  of 
moisture,  some  of  which  comes  to  the  earth.  When  the 
air  is  full  of  moisture  which  does  not  fall,  the  weather 
may  be  as  disagreeable  as  on  stormy  days.  On  damp, 
cold  days  the  winds  that  strike  us  cut  like  a  knife,  chill- 
ing us  with  the  moisture  which  they  bring.  If  the  day 
be  very  warm  and  moist,  as  it  is  frequently  during  the 
so-called  dog  days  of  summer,  we  feel  sticky  and  lazy,  and 
very  uncomfortable.  Again,  a  very  dry,  hot  day  may  be 
equally  disagreeable,  because  the  moisture  that  is  lack- 
ing in  the  air  must  be  supplied  in  part  from  ourselves 
through  evaporation.  As  we  have  certain  days  in  the 
year  that  are  very  moist,  and  some  that  are  very  dry,  so 
in  certain  parts  of  the  world  the  average  climate  is  wet 
or  dry.  Those  regions  that  are  excessively  dry  are  des- 
erts, and  those  that  are  excessively  moist,  other  condi- 
tions being  favorable,  may  be  covered  with  luxuriant 


WEATHER   AND    CLIMATE.  1/5 

vegetation,  or  filled  with  swamps,  which  are  mostly  unin- 
habitable, owing  in  part  to  the  moisture,  and  in  part  to 
the  fact  that  severe  fevers  are  prevalent  in  such  regions. 

When  there  is  a  sufficient  amount  of  moisture  in  the 
air  to  fall  as  rain  or  snow,  it  is  necessary  to  catch  the 
falling  moisture  and  to  measure  it  in  order  to  get  a  clear 
knowledge  of  the  amount  of  rainfall  during  a  year.  If 
the  fall  be  in  the  form  of  snow,  it  is  measured  in  its 
liquid  form  as  water.  The  number  of  inches  that  fall 
over  a  given  surface  in  a  year  gives  us  the  rainfall  of  the 
region,  a  very  important  matter  in  determining  the  suc- 
cess of  agriculture. 

In  speaking,  then,  of  the  weather  we  mean :  first,  that 
it  is  clear,  cloudy,  or  stormy;  second,  that  it  is  warm  or 
cold ;  third,  that  the  air  is  light  or  heavy;  fourth,  that 
the  air  is  wet  or  dry,  and,  if  it  rains  or  snows,  that  the 
rainfall  is  heavy  or  light.  It  is  the  average  of  these  sev- 
eral things  that  goes  to  make  up  climate,  and  as  these 
factors  may  occur  in  almost  any  combination,  it  is  pos- 
sible to  have  almost  any  kind  of  climate  in  the  different 
parts  of  the  world. 

We  shall  find,  however,  that  the  other  features  vary 
more  or  less  with  the  temperature,  and  that  a  knowledge 
of  the  distribution  of  temperature  over  the  world  will  give 
us  a  suggestion  as  to  the  other  features  of  the  climate. 


CHAPTER   XVII. 
TEMPERATURE. 

Measurement  of  Temperature. — When  we  speak  of 
temperature,  we  mean  the  temperature  of  the  air  close 
to  the  surface  of  the  earth,  and  we  measure  this  tem- 
perature by  means  of  a  thermometer.  A  thermometer 
usually  consists  of  a  glass  tube  with  a  bulb  at  the  bottom 
containing  a  certain  amount  of  mercury,  which  is  a  liquid 
metal  that  readily  changes  its  volume  as  it  grows  warm 
or  cold.  The  tube  of  mercury  is  placed  in  freezing  water, 
and  a  mark  is  made  on  the  glass  at  the  surface  of  the 
mercury  after  it  comes  to  rest.  This  mark  in  the  ordinary 
thermometers  in  every-day  use  is  called  32°,  or  the  freez- 
ing point.  In  a  similar  way  the  position  of  the  mercury 
in  the  tube  is  found  when  the  tube  is  in  boiling  water, 
this  point  being  labelled  212°,  or  boiling  point.  The 
space  between  is  divided  into  180  equal  parts,  or  degrees, 
and  in  a  similar  way  the  tube  below  the  freezing  point  is 
divided  into  equal  degrees.  Thermometers  divided  in 
this  way  are  known  as  Fahrenheit  thermometers;  and 
when  we  speak  of  a  temperature  of  10°,  or  56°,  or  100°, 
we  mean  a  temperature  sufficient  to  raise  the  mercury  in 
such  a  Fahrenheit  thermometer  to  the  point  indicated. 
The  zero  line  is  32°  below  freezing,  and  below  that  point 
we  measure  the  degrees  from  the  zero  limit,  so  that  a 
temperature  of  6°  below  zero,  which  is  a  very  unusual 
temperature  for  New  York  City,  means  in  reality  38° 
below  the  freezing  point. 


SOURCE   OF   EARTH    HEAT.  177 

In  some  thermometers  the  freezing  point  is  marked 
zero,  and  the  boiling  point  100°.  In  such  instruments 
the  degrees  are  consequently  larger  than  in  a  Fahrenheit 
thermometer,  there  being  but  one  hundred  instead  of 
one  hundred  and  eighty  degrees  in  the  same  space.  We 
will  refer  continually  to  Fahrenheit  temperatures,  which 
in  our  ordinary  experience  range  from  something  over 
1 00°  in  the  shade  to  a  temperature  of  a  little  below  zero. 
A  permanent  temperature  of  much  over  100°  could  not 
be  endured  by  men. 

Source  of  Earth  Heat.— The  heat  that  comes  to  the 
lower  portion  of  the  atmosphere,  the  portion  in  which  we 
live,  comes  almost  entirely  from  the  sun.  The  tempera- 
ture of  the  air  depends  primarily  upon  two  things,  the 
amount  of  heat  received  and  the  amount  that  is  retained 
by  the  atmosphere.  The  amount  received  depends 
almost  entirely  upon  the  angle  at  which  the  rays  of  heat 
strike  the  earth.  We  know,  for  instance,  that  in  the 
morning  and  evening, .when  the  sun  lies  low  in  the  hori- 
zon, our  shadow  is  several  times  our  own  length.  We 
can  see  that  the  amount  of  light  and  heat  which  strikes 
us,  and  which  is  prevented  from  passing  on,  would,  were 
we  not  there,  be  spread  over  an  area  approximately  as 
large  as  our  shadow,  which  is  many  times  the  area  that 
we  expose  to  the  light  and  heat.  As  the  whole  of  our 
shadow  could  not  receive  any  more  light  or  heat  than 
we,  it  is  very  evident  that  any  part  of  the  shadow  must 
receive  a  very  small  proportion  of  the  light  and  heat  that 
would  come  to  it  at  noon  time  in  midsummer,  when  the 
sun  is  high  in  the  heavens  and  our  shadow  but  little 
larger  than  ourselves.  It  is  very  easily  seen,  therefore, 
that,  the  more  directly  the  rays  of  light  and  heat  strike 
an  object,  the  more  that  object  will  be  heated  or  lighted, 

12 


178  A  READER   IN   PHYSICAL  GEOGRAPHY. 

for  the  more  heat  or  light  will  be  spread  over  a  given 
area. 

As  the  rays  of  energy  strike  us  obliquely  in  the  morning 
and  evening,  and  more  nearly  vertically  at  noon,  giving 
us  a  weak  amount  or  a  large  amount  of  heat  to  a  given 
surface,  so  there  are  parts  of  the  world  where  the  rays  of 
light  and  heat  come  very  directly  throughout  a  larger 
part  of  the  year,  and  other  portions  where  the  rays  are 
more  slanting.  There  are  still  other  regions  where,  at 
certain  seasons,  no  rays  come  at  all,  because  that  portion 
of  the  earth  is  turned  away  from  the  sun.  This  is  the 
case  in  the  north  polar  regions  in  January  (our  winter) 
and  the  south  polar  regions  in  July  (the  southern  winter). 

The  effect  of  the  more  direct  and  the  more  slanting  rays 
of  the  sun  is  clearly  seen  by  comparing  a  southern  and  a 
northern  hillside  in  winter.  The  northern  slope,  receiv- 
ing the  more  slanting  rays,  is  the  colder.  Hence  the 
snow  lingers  there  much  longer  than  on  the  southern 
slope,  which,  exposed  to  the  more  direct  rays  of  the  sun, 
is  consequently  warmer  than  the  northern.  It  is  for  this 
reason  that  a  poultry  keeper  builds  his  henhouse  with 
the  windows  to  the  south,  and  with  the  sloping  roof  to 
the  north,  so  as  to  get  as  much  surface  as  possible  ex- 
posed directly  to  the  rays  of  the  winter  sun. 

The  Motions  of  the  Earth. — We  already  know  that 
the  earth  is  spinning  like  a  top,  turning  around  once  in 
what  we  call  twenty-four  hours,  or  a  day,  giving  us  day- 
light when  our  portion  of  the  earth  is  directed  toward  the 
sun's  rays,  and  darkness  when  we  have  the  earth  between 
us  and  the  sun.  The  earth  does  not  spin,  however,  ex- 
actly as  a  top,  as  its  axis,  or  the  central  line  about  which 
it  turns,  is  not  vertical,  but  in  a  slanting  position.  Some- 
times a  top  will  spin  for  a  moment  about  a  slanting  axis 


THE   MOTIONS   OF  THE   EARTH.  179 

just  before  it  falls;  then  it  is  in  a  similar  position  to  that 
of  the  earth  at  all  times.  On  the  earth,  as  on  the  top, 
the  portion  of  the  surface  half-way  between  the  station- 
ary poles,  or  ends,  of  the  axis  moves  more  rapidly  than 
any  other  portion,  because  the  points  along  this  line 
have  to  go  farther  in  one  revolution  than  any  other  por- 
tion. This  half-way  line  of  greatest.motion  is  called  the 
equator. 

As  the  earth  spins,  it  moves  around  the  sun  in  a  nearly 
circular  course,  much  as  a  spinning  top  may  move  across 
the  floor.  Perhaps  the  motion  can  be  illustrated  better 
by  floating  an  apple  in  a  large  pan  of  water,  about  some 
fixed  object  in  the  centre,  representing  the  sun.  If  we 
have  the  apple  in  such  a  position  that  the  line  from  the 
stem  end  to  the  bloom  end  is  in  a  slanting  position  similar 
to  the  axis  of  the  earth,  the  stem  end  standing  for  the 
North  Pole  of  the  earth  and  the  opposite  point  for  the 
South  Pole,  we  can  easily  illustrate  how  the  several  parts 
of  the  earth  lie  with  reference  to  the  heat-giving  sun. 

It  is  easy  to  see  that  there  is  a  broad  belt  on  two  sides 
of  the  equator  within  which  the  sun  always  shines  verti- 
cally; that  is,  somewhere  in  this  region  the  sun  at  noon 
would  be  directly  overhead  to  one  lying  on  his  back  and 
looking  upward.  The  limits  to  this  area  on  the  earth 
are  known  as  the  tropics,  from  a  Greek  word  meaning  "to 
turn,"  because  the  sun  seems  at  these  limits  to  turn  in 
its  course,  though,  of  course,  it  is  the  earth  that  changes 
in  relation  to  the  sun,  rather  than  the  sun  in  relation  to 
the  earth.  The  northern  tropic  is  known  as  the  Tropic 
of  Cancer,  and  the  southern  as  the  Tropic  of  Capricorn. 

Similarly,  we  can  see  that  there  are  certain  parts  of  the 
earth  about  the  poles  that  are,  during  certain  seasons, 
turned  away  from  the  sun,  so  that  the  earth  cuts  off 


180  A   READER   IN   PHYSICAL   GEOGRAPHY. 

any  rays  of  light  and  heat,  just  as  in  the  night  the 
earth  itself  cuts  off  the  light  from  the  portions  in  dark- 
ness. The  limit  to  the  north  polar  region  within  which 
the  sun  does  not  shine  during  some  part  of  the  year 
is  known  as  the  Arctic  Circle,  and  the  limit  to  the  simi- 
lar southern  region  is  known  as  the  Antarctic  Circle. 
Between  the  circles  and  the  tropics,  in  both  the  north- 
ern and  southern  hemispheres,  lie  the  regions  within  some 
part  of  which  the  sun  always  shines,  but  never  vertically. 
It  should  be  noted,  however,  that  when  either  polar 
region  is  all  lighted,  the  area  between  the  circle  and  the 
tropic  receives  its  rays  at  a  more  direct  angle  than  at 
other  times,  and  that  at  that  time  the  sun  is  vertical  on 
that  side  of  the  equator. 

Zones  and  Heat  Belts. — Were  all  the  heat  that  is 
received  from  the  sun  within  these  several  areas  of  the 
earth  retained  at  the  place  where  it  is  received,  the  tropics 
and  the  circles  would  very  naturally  divide  the  world 
into  five  great  climatic  divisions,  known  as  the  tropical 
zone,  the  north  and  south  temperate  zones,  and  the  frigid 
zones,  each  zone  being  a  very  definite  and  straight- 
edged  belt  about  the  earth,  although  it  would  be  better 
to  speak  of  the  frigid  zones  as  polar  caps  rather  than  as 
belts. 

Inasmuch,  however,  as  all  parts  of  the  world  cannot 
retain  the  heat  that  comes  to  them  with  equal  readiness, 
we  find  that  the  climatic  divisions  of  the  world  are  not 
quite  so  regular  as  the  idea  of  zones  would  lead  us  to 
expect.  The  climatic  divisions  of  the  earth  are  known 
as  heat  belts,  and  are  determined  in  their  bounds,  not 
by  the  amount  of  heat  received,  but,  as  has  already  been 
suggested,  by  the  amount  retained. 

Were  all  portions  of  the  earth  capable  of  retaining  heat 


ZONES  AND   HEAT  BELTS.  l8l 

with  equal  ease,  the  temperature  of  a  place  would  prac- 
tically be  determined  by  the  angle  at  which  the  rays  of 
the  sun  strike  the  earth  at  that  spot.  As  a  matter  of 
fact,  however,  the  heat  absorbed  by  the  earth  in  the  day- 
time is  to  a  large  extent  given  out  in  the  night,  and  that 
received  and  absorbed  during  the  hot  parts  of  the  year  is 
given  out  in  the  cold  season. 

Furthermore,  the  land  areas  of  the  world  absorb  heat 
more  quickly,  and  give  it  out  more  quickly,  than  the 
water;  that  is,  water  once  heated  will  stay  warm  longer 
than  the  rocks  of  the  land,  but  it  takes  a  longer  time 
to  warm  the  water  than  the  land.  The  fact  that  land 
and  water  differ  in  their  rate  of  absorbing  heat  explains 
the  reason  why  the  swimming  season  comes  long  after 
the  ground  is  warm  enough  to  sit  on  in  the  spring,  and 
why  the  water  is  warm  for  swimming  in  the  autumn 
when  the  air  may  be  too  cold  for  comfortable  bathing. 
The  same  thing  is  shown  by  the  present  use  of  hot-water 
bottles  rather  than  soapstones  as  a  means  of  keeping  one 
warm  when  riding  or  sleeping.  It  is  for  this  reason  that 
the  lands  are  hotter  in  the  summer  and  colder  in  the 
winter  than  the  adjacent  oceans,  which  receive  from  the 
sun  the  same  amounts  of  heat.  It  is  very  evident,  also, 
that  no  part  of  the  world  absorbs  more  heat  than  it  after- 
wards gives  out,  for  if  it  did,  the  world' would  be  becom- 
ing warmer  each  year;  or  if  it  gave  out  more  than  it 
absorbed,  it  would  be  becoming  colder. 

When  bodies  of  different  temperatures  are  near  to  one 
another,  there  is  a  tendency  for  the  temperature  to  become 
equally  distributed.  It  is  for  this  reason  that  the  land 
and  the  water  are  giving  up  their  heat  to  the  adjoining 
air  in  the  nights  and  winters,  as  has  been  suggested. 
Were  the  warm  waters  of  the  oceans  to  remain  at  rest 


1 82  A    READER   IN   PHYSICAL   GEOGRAPHY. 

during  the  winter  and  summer  seasons,  they  would  un- 
doubtedly be  subjected  to  greater  changes  of  tempera- 
ture than  they  now  are;  but  we  have  already  seen  that 
there  are  in  each  of  the  great  oceans  a  series  of  ocean 
currents  which  are  continually  carrying  the  warmer  waters 
from  the  tropical  region  polewards,  and  the  colder  waters 
from  the  polar  regions  toward  the  equator.  This  move- 
ment of  the  oceanic  waters  is  the  most  important  cause 
for  the  unequal  distribution  of  temperatures  over  the 
world,  inasmuch  as  some  of  the  heat  received  in  certain 
parts  of  the  earth  is  carried  to  less  favored  places. 

It  is  evident,  therefore,  that  on  the  whole  we  should 
expect  those  regions  at  a  distance  from  the  equator  to 
have  an  average  climate  colder  than  those  regions  near 
the  equator;  and  furthermore,  that  in  the  equatorial 
regions  the  lands  would  be  permanently  warmer  than  the 
oceans,  whereas  in  the  temperate  regions  the  lands  would 
be  warmer  in  the  summer  and  cooler  in  the  winter  than 
the  adjoining  ocean.  We  have  seen,  also,  that  the  move- 
ment of  the  ocean  currents  in  the  northern  hemisphere 
is  such  that  the  westward  sides  of  the  continents  are 
warmer  than  the  eastern,  being  bathed  by  the  warm 
ocean  waters ;  so  the  fact  that  the  world  is  made  of  land 
and  water,  and  that  the  water  is  in  motion,  is  an  impor- 
tant cause  for  the  variation  of  temperature  in  any  zone. 

The  heavier,  lower  air  in  which  we  live  is  the  warmer, 
and  as  one  rises  into  the  upper,  lighter  air,  less  heat  is 
received  from  the  earth.  Hence  we  can  get  practically 
the  same  range  in  temperatures  by  climbing  a  high 
mountain  in  the  tropics  as  we  can  by  going  from  the 
tropics  to  the  polar  regions;  and  highlands  are,  as  a  rule, 
colder  than  the  adjacent  lowlands.  This  is  beautifully 
illustrated  along  the  line  of  the  famous  railway  in  Peru, 


ZONES  AND    HEAT   BELTS.  183 

that  goes  from  sea  level  to  an  altitude  of  over  15,000 
feet,  and  thence  down  to  about  12,000  feet.  '  The  first 
part  of  the  journey  is  through  fields  of  sugar-cane  and 
cotton ;  at  5,000  feet  a  zone  of  fruit  trees  is  passed 
through;  at  10,500  feet  there  is  a  district  famous  for  its 
potatoes  where  little  else  is  grown ;  above  this  the  alti- 
tude is  so  great  as  to  preclude  the  growth  of  anything 
but  grass.  At  the  highest  point  reached  the  snow  lies 
on  the  mountain  summits  throughout  the  year,  and  the 
traveller  may  enjoy  a  snowstorm  in  the  middle  of  sum- 
mer (December-February).  In  the  interior  valley,  farm 
produce  is  again  seen  growing.  This  whole  succession 
of  climates  may  be  passed  through  in  the  short  space  of 
ten  hours."  * 

The  parts  of  the  world  in  which  the  temperature  is  on 
the  average  below  freezing — that  is,  less  than  32°  Fahren- 
heit— are  spoken  of  as  the  cold  belts.  We  have  thus  a 
northern  and  a  southern  cold  belt.  Where  the  tempera- 
ture is  on  the  average  above  freezing,  and  less  than  68° 
-Fahrenheit,  it  is  known  as  the  cool,  or  temperate  belt; 
about  the  hottest  regions  of  the  world,  where  over  the 
land,  at  least,  the  average  temperature  is  above  80°,  we 
have  the  hot  belt ;  and  between  the  hot  and  cool,  or  tem- 
perate belts,  we  have  the  warm,  sometimes  called  the  sub- 
tropical belt.  These  several  belts  are  known  as  heat 
belts,  and  differ  very  much  in  their  limits  from  the  zones. 

The  division  of  the  world  into  heat  belts  becomes  more 
possible  each  year,  as  we  learn  more  and  more  of  the 
climatic  conditions  of  the  world  as  a  whole. 

It  is  possible,  of  course,  to  find  out  the  average  tem- 
perature conditions  of  any  spot  on  the  earth  at  which 

*R.  DeC.  Ward,  Climatic  Notes  made  during  a  Voyage  around  South 
America,  Jour.  Sch.  Geog.,  October,  1898,  p.  309. 


1 84  A   READER   IN   PHYSICAL  GEOGRAPHY. 

observation  for  temperature  has  been  carried  on  for  a 
long  time.  If  we  then  represent  these  conditions  on  a 
map,  and  connect  them  by  lines,  we  can  by  means  of 
these  lines  indicate  the  position  of  all  points  having  the 
same  average  temperature  for  any  given  time.  Such 
lines  are  known  as  isotherms  (equal  heat),  because  all  the 
points  along  them  have  equal  temperatures.  A  study  of 
the  map  showing  the  isotherms  of  the  world  for  the  year, 
or  for  the  different  seasons,  will  therefore  tell  us  much  in 
reference  to  the  temperature  and  the  other  conditions 
depending  upon  temperature. 

Were  the  sun's  rays  always  vertical  at  the  same  point, 
there  would  be  a  line  about  the  earth  having  the  greatest 
average  temperature,  pretty  nearly  coinciding  with  the 
equator.  As  we  have  already  seen,  however,  the  sun  in 
the  summer  season  is  shining  vertically  somewhere  north 
of  the  equator,  and  in  the  winter  season  south  of  the 
equator;  therefore,  the  line  of  places  receiving  the  great- 
est amount  of  heat  moves  north  or  south  with  the  change 
of  season.  The  land  areas  would,  for  the  several  reasons 
we  have  already  suggested,  become  much  warmer  than 
the  water  areas,  and  therefore,  owing  to  the  fact  that 
there  is  much  more  land  in  the  northern  hemisphere  than 
in  the  southern,  we  should  find  the  extremely  hot  region 
extending  farther  north  from  the  equator  than  south  of 
it.  This  line  of  greatest  heat  is  commonly  called  the 
heat  equator,  and  on  the  average  lies,  for  the  reasons  we 
have  suggested,  north  rather  than  south  of  the  equator, 
although  in  the  northern  winter  it  is  mostly  south  of  the 
equator.  The  region  over  which  the  heat  equator  swings 
during  the  year  is  commonly  known  as  the  hottest  heat 
belt. 


CHAPTER   XVIII. 
WINDS    AND    RAINFALL. 

WE  are  all  familiar  with  the  upward  movement  of 
heated  air  and  the  downward  movement  of  cold  air 
in  a  room  ;  in  order  that  this  hot  air  may  escape 
easily,  we  usually  open  a  window  at  the  top  rather 
than  at  the  bottom.  We  also  know  that  air,  being  able 
to  move  with  perfect  ease,  and  the  hotter  air  being  on 
the  top,  the  hot  air  is  the  lighter,  and  the  cold  air  the 
heavier.  In  a  similar  way  we  should  expect,  on  the 
whole,  that  the  weight  of  the  air,  or,  as  we  say,  the  pres- 
sure, would  be  less  in  those  parts  of  the  earth  where  the 
temperature  is  highest,  and  greater  in  the  colder  por- 
tions. We  should  also  expect  the  air  to  be  moving  con- 
tinually from  the  regions  of  greater  pressure  to  the  regions 
of  lesser  pressure,  or  from  the  two  sides  of  the  heat 
equator  toward  the  heat  equator. 

The  air  from  the  two  sides  of  the  heat  equator  is  con- 
tinually moving  in  toward  the  region  of  low  pressure,  or 
of  light  air  at  the  heat  equator,  the  winds  brought  about 
by  this  movement  being  familiarly  known  as  the  trade 
winds.  As  the  air  rises  when  it  reaches  the  heat  equator, 
there  would  be  no  movement  of  air  along  the  ground,  or, 
as  we  say,  no  wind,  but  rather  a  calm  in  this  region. 
This  belt  of  calms,  with  its  quiet,  warm,  breathless  air, 
is  well  known  to  all  travellers  who  have  to  cross  the 
equator,  and  is  a  very  perplexing  and  disagreeable  fea- 
ture to  the  master  of  a  sailing-vessel,  who  depends  upon 


1 86  A  READER   IN   PHYSICAL  GEOGRAPHY. 

wind  for  his  means  of  motion,  and  who  may  be  detained 
for  days,  waiting  for  even  a  breath.  This  belt  of  calms 
about  the  equator,  and  closely  coinciding  with  the  heat 
equator,  is  familiarly  known  as  the  doldrums. 

On  the  outer  side,  or  toward  the  poles  from  the  trade- 
wind  belts,  a  little  north  and  south  from  the  tropics,  we 
find  a  region  where  the  air  which  has  risen  at  the  equator 
and  started  toward  the  poles  begins  to  settle,  thereby 
increasing  the  weight  of  the  air  in  that  region.  In  these 
two  belts,  known  as  the  horse  latitudes,  the  air  being  in 
motion  vertically  rather  than  along  the  ground,  there 
are  again  calms,  and  from  these  two  belts  the  air  moves 
north  and  south  toward  the  poles  and  the  equator.  Be- 
tween the  horse  latitudes  and  the  polar  regions  are  two 
broad  belts,  in  the  northern  one  of  which  we  live,  which 
are  known  as  the  belts  of  the  stormy  westerly  winds. 
Those  winds  in  general  blow  from  the  southwest  in  this 
hemisphere,  and  from  the  northwest  in  the  southern 
hemisphere,  in  which  latter  region  they  are  much  more 
persistent  and  strong,  owing  to  the  free  and  uninter- 
rupted sweep  they  have  over  the  waters  of  the  southern 
ocean.  From  their  position  and  their  strength  the  south- 
ern westerly  winds  are  commonly  known  as  the  roaring 
forties.  Finally,  about  the  poles  we  have  a  series  of  cold 
winds  blowing  outward  from  the  poles,  and  commonly 
known  as  polar  winds. 

We  have  already  seen  that  the  several  belts  of  temper- 
ature swing  north  and  south  with  the  apparent  yearly 
motion  of  the  sun,  and  in  the  same  way  we  must  expect 
the  wind  systems  to  swing  north  and  south,  so  that  certain 
parts  of  the  world  will  be  blown  over  by  one  system  of 
winds  in  the  summer,  and  another  in  winter.  This  feature 
is  well  illustrated  in  the  southwestern  United  States, 


WINDS   AND   RAINFALL.  1 87 

where  in  winter  the  westerly  winds  prevail  and  in  sum- 
mer the  trades. 

In  our  own  temperate  regions  the  stormy  westerly 
winds  are  interrupted  in  their  force,  particularly  over  the 
land,  because  of  differences  in  temperature  between  the 
land  and  water.  In  the  winter,  when  the  land  is  so  much 
colder  than  the  water  that  St.  Louis,  New  York  City, 
and  southern  Iceland  have  practically  the  same  tempera- 
tures, the  air  over  the  continents  is  not  only  much  colder, 
but  much  heavier  than  over  the  ocean.  Consequently 
our  fair-weather  winds  blow  outward  from  the  continents 
to  the  oceans,  as  is  well  illustrated  by  the  familiar  winter 
northwest  wind  of  the  Eastern  United  States.  In  a 
similar  way  in  the  summer  the  winds  blow  from  the 
oceans  toward  the  land,  the  air  on  the  land  being  lighter 
and  warmer  than  that  of  the  ocean. 

This  effect  of  land  and  water  upon  the  movement  of 
the  air  is  well  illustrated,  at  certain  seasons  of  the  year, 
along  our  eastern  coast,  by  the  change  in  direction  of  the 
winds  during  the  daytime.  In  the  morning  the  air  over 
the  land  is  colder  and  heavier  than  over  the  ocean,  and 
hence  the  winds  blow  from  the  land  to  the  sea;  during 
the  forenoon  the  air  over  the  land  gets  warm  faster  than 
over  the  sea,  so  that  about  noon,  or  perhaps  a  little  after 
noon,  the  air  over  the  land  is  warmer  and  lighter  than 
the  ocean  air.  As  a  result,  the  colder  air  of  the  ocean 
moves  in  toward  the  land,  giving  us,  in  the  season  when 
such  cool  ocean  air  is  agreeable,  what  we  call  a  sea  breeze. 
In  the  spring  of  the  year,  when  this  air  chills  us  dis- 
agreeably, we  commonly  call  it  an  east  wind.  The 
same  change  from  night  land  breezes  to  day  sea  breezes 
frequently  occurs  on  the  borders  of  large  lakes,  so 
that  the  lake  breeze  of  Chicago,  for  instance,  does  for 


1 88  A   READER  IN   PHYSICAL   GEOGRAPHY. 

Chicago  what  the  sea  breeze  does   for  New  York  and 
Boston. 

This  change  of  direction  going  on  in  a  single  day  in 
certain  parts  of  the  year  is  but  a  small  illustration  of 
the  great  changes  taking  place  during  the  whole  year, 
between  the  continent  fair-weather  winds  of  winter  and 
the  ocean  fair-weather  winds  of  summer,  which  have 
already  been  mentioned.  Besides  these  several  systems 
of  winds,  each  dependent  upon  differences  of  weight  of 
the  air,  brought  about  by  changes  of  temperature,  we,  in 
the  so-called  temperate  regions,  are  subjected  to  very 
rapid  changes  of  wind,  and  sometimes  of  weather,  which 
are  brought  about  by  the  severe  storms  which  pass  over 
us,  interrupting  the  fair-weather  conditions  that  we  have 
for  the  larger  part  of  the  time. 

Moisture  and  Rainfall. — The  element  in  the  weather 
of  a  region  which  determines  what  we  call  the  character 
of  the  day  is  the  moisture.  It  is  moisture  also  that,  next 
to  temperature,  makes  the  climate  of  certain  regions  en- 
durable, and  of  others  perhaps  hardly  bearable,  and  it  is 
on  the  moisture  and  temperature  that  all  growth  of 
plants  depends.  Moisture  exists  in  all  air  to  a  certain 
extent,  in  the  form  of  invisible  water  vapor.  Even  in 
deserts  the  air  is  not  wholly  free  from  moisture,  though 
it  may  seem  to  be  to  those  who  are  suffering  from  the 
discomforts  of  the  region.  The  fact  that  moisture  in  the 
air  may  be  invisible  is  perhaps  best  shown  by  looking 
at  the  mouth  of  a  rapidly  boiling  tea-kettle,  and  by 
noticing  that  for  a  certain  distance  from  the  mouth  noth- 
ing can  be  seen,  whereas  beyond  that  we  find,  a  small 
cloud  of  what  we  call  steam.  Steam  forms  when  the 
invisible  vapor  has  cooled  and  accumulated  in  little  drops 
that  make  clouds. 


MOISTURE   AND    RAINFALL.  189 

Moisture  is  taken  up  into  the  air  from  any  wet  surface, 
or,  as  we  say,  evaporated,  through  the  influence  of  heat. 
Many  hot-air  furnaces,  for  instance,  are  supplied  with 
pans  for  holding  water  to  be  evaporated  and  carried  to 
the  rooms  above  by  the  heated  air,  making  the  air  more 
healthful  and  agreeable.  It  is  the  invisible  moisture  in 
the  air  that  makes  certain  warm,  so-called  sultry  days  in 
the  summer  so  unpleasant,  and  it  is  the  moisture  in  the 
air  in  the  winter  that  makes  certain  days  so  chilly  and 
disagreeable.  Hot  air  will  include  much  more  invisible 
vapor  than  cold  air.  Hence  if  warm  air  containing  a  large 
amount  of  moisture  be  chilled  to  a  sufficient  extent,  the 
vapor  will  form  into  drops,  or,  as  we  say,  condense;  and 
if  the  amount  be  very  much  greater  than  what  the  air  can 
hold,  some  of  those  drops  become  so  large  that  they  fall 
to  the  earth,  under  the  pull  of  gravity,  giving  us  rain  or 
snow. 

It  is  the  moisture  condensing  at  high  levels  in  the  air 
that  forms  clouds.  When  the  air  is  full  of  fine  drops  of 
moisture  down  to  the  very  surface  of  the  earth,  we  have 
a  mist;  or  if  very  thick,  we  call  it  a  fog.  In  most  nights 
of  the  summer,  moisture  condenses  on  the  cool  surface 
of  the  rocks,  or  the  grass,  or  leaves,  and  we  know  it  as 
dew.  In  a  moist  summer  day  the  vapor  of  the  atmos- 
phere chills  and  forms  dew  on  an  ice  pitcher,  and  in  the 
winter  the  moisture  of  our  breath  forms  a  little  cloud, 
or  perhaps  condenses  and  freezes  as  frost  on  the  windows 
of  our  rooms,  covering  them  deeply. 

When  the  moisture  in  the  air  becomes  so  great  that 
the  drops  fall  to  the  earth,  we  have  rain ;  if  that  water 
freezes  in  its  descent,  we  may  have  snow,  or  possibly 
sleet,  or,  under  exceptional  conditions,  large  lumps  of 
ice,  which  we  call  hailstones,  may  be  formed  in  the  airr 


IQO  A   READER  IN   PHYSICAL   GEOGRAPHY. 

It  has  already  been  noted  that  moisture  may  be  evapo- 
rated from  any  part  of  the  earth's  surface  which  is  wet. 
The  oceans  and  larger  lakes  of  course  supply  the  greater 
proportion  of  the  moisture,  and  very  naturally  it  is  the 
water  in  the  hot  belts  of  the  earth  that  is  taken  up  most 
rapidly  into  the  air.  In  any  case  the  moisture  of  course 
is  carried  by  the  prevailing  winds,  and  any  conditions 
over  the  land  which  cause  the  winds  to  be  chilled  as  they 
move,  bring  about  rainfall. 

The  larger  cause  for  rainfall  over  the  land  is  due  to  the 
fact  that  the  land  is  rugged,  and  that  the  air  must  rise  to 
move  across  the  continents.  As  the  air  rises,  it  cools 
rapidly,  as  we  have  already  seen,  and  hence  loses  its 
power  for  carrying  moisture.  As  a  result,  heavy  rain- 
falls occur  in  those  parts  of  the  world  where  the  prevail- 
ing winds  blow  from  water  to  land,  and  where  mountain 
ranges  are  found  close  to  the  sea.  For  instance,  the 
rainy  portion  of  the  United  States  is  in  Washington, 
Oregon,  and  southern  Alaska,  where  the  Coast  Range 
causes  the  moisture-bringing  wind  to  supply  an  abundant 
rainfall,  a  large  part  of  this  coast  receiving  more  than  75 
inches  of  rain  on  every  square  inch  of  surface  during  the 
year.  In  1899  certain  parts  of  the  coast  of  Oregon  re- 
ceived more  than  100  inches. 

The  same  effects  of  highlands  upon  rainfall  are  shown 
in  South  America.  In  the  trade-wind  belt  the  wind 
blows  from  the  Atlantic  Ocean  across  the  continent,  and 
is  not  forced  to  rise  to  any  great  height  until  it  comes  to 
the  western  side  of  the  Amazon  Basin,  at  the  foot  of  the 
Andes  Mountains.  As  a  result,  the  Amazon  Basin  and 
the  Eastern  Andes  have  a  heavy  rainfall,  it  being  more 
than  80  inches  a  year,  whereas  the  coast  strip  on  the 
western  side  of  the  Andes  is  practically  dry.  As  we  go 


DESERTS   AND   ARID    REGIONS.  IQI 

farther  south,  particularly  into  southern  Chile,  where  we 
find  the  westerly  winds  striking  the  Pacific  side  of  the 
Andes,  we  again  have  a  heavy  rainfall ;  whereas  the  coun- 
try on  the  leeward  side  of  the  highlands  is  again  practi- 
cally a  desert,  some  parts  of  it  receiving  less  than  ten 
inches  of  rainfall  during  a  year.  A  similar  illustration 
of  the  effect  of  highlands  on  rainfall  is  shown  in  the 
highlands  of  Brazil  along  the  southeast  coast,  where 
we  find  the  rainfall  again  more  than  75  inches. 

Deserts  and  Arid  Regions. — The  fact  that  regions  on 
the  leeward  sides  of  mountain  ranges  are  usually  dry  is 
beautifully  illustrated  in  the  southwestern  United  States, 
just  east  of  the  Sierra  Nevada  Mountains,  and  west  of 
the  so-called  Rocky  Mountains,  where  the  rainfall  is 
less  than  ten  inches,  and  in  some  places  less  than  five 
inches  a  year.  Yuma,  Arizona,  in  the  Yuma  Desert, 
received  less  than  an  inch  of  rain  in  1899.  Perhaps  the 
best  illustration  in  the  world  is  shown  in  Australia,  where 
the  eastern  highlands  receive  a  rainfall  amounting  in 
places  to  nearly  75  inches  in  a  year,  while  the  interior 
region  is  one  great  desert,  with  so  little  rainfall  that 
certain  parts  of  it  are  practically  unexplored,  even  at 
the  present  time. 

As  a  rule,  therefore,  we  may  say  that  the  windward 
sides  of  continents  are  moist,  and  the  leeward  sides  dry, 
although  there  is  a  certain  apparent  exception  to  this  in 
the  eastern  United  States,  which  has  an  abundant  and 
sufficient  amount  of  rainfall  for  all  purposes  of  agricul- 
ture and  life.  The  moisture  here,  however,  is  brought 
from  the  Gulf  of  Mexico  and  the  Great  Lakes,  in  part  by 
the  prevailing  winds  and  in  part  by  the  storms. 

When  winds  blow  from  a  cold  to  a  warm  region,  and 
at  the  sarne  time  blow  across  the  land  to  get  to  that 


192  A   READER   IN   PHYSICAL  GEOGRAPHY. 

warm  region,  they  not  only  become  better  able  to  carry 
moisture  in  an  invisible  form,  but,  blowing  over  a  region 
that  can  furnish  but  little  moisture,  they  leave  that 
region  much  drier  than  they  found  it;  or,  in  other  words, 
turn  it  into  a  desert.  The  best  illustration  that  we  have 
of  this  manner  of  forming  deserts  is  perhaps  shown  in 
the  case  of  the  Sahara,  the  same  distance  from  the  equa- 
tor as  our  own  well-watered  Florida  and  the  eastern 
coast  of  Central  America.  The  winds  that  cross  the 
Sahara  on  their  way  to  the  heat  equator  are  dry  when 
they  start  from  the  horse-latitude  belt.  Originating  as 
they  do  over  the  land,  they  become  more  and  more  dry 
as  they  become  warmer  and  warmer,  and  hence  better 
able  to  hold  moisture.  In  Central  America,  on  the  con- 
trary, the  trades,  coming  from  over  the  ocean,  have  their 
moisture  supplied  to  them  as  rapidly  as  they  need  it,  and 
when  they  reach  the  land,  naturally  furnish  a  large  sup- 
ply of  rainfall.  Were  the  Atlantic  Ocean  a  land  surface, 
Central  America  would  be  as  dry  as  the  Sahara,  and  were 
the  continent  of  Eurasia  a  body  of  water,  the  Sahara 
would  have  as  heavy  a  rainfall  as  Central  America. 

The  ability  of  the  warming  winds  to  take  moisture 
from  the  water  is  well  shown  by  the  fact  that  the  trade- 
wind  belts  of  the  oceans  are  salter  than  are  the  oceans  to 
the  north  and  south.  This  is  due,  of  course,  to  the  fact 
that  the  moisture  evaporated  is  pure  water,  which  leaves 
behind  the  salt,  making  the  water  that  remains  more  salt 
than  it  would  otherwise  be. 

Rainfall  of  the  World.— In  looking  at  the  rainfall  of 
the  world  as  a  whole,  we  find  certain  striking  relations  to 
the  several  heat  belts  that  have  been  mentioned.  The 
cold  belt  in  the  northern  hemisphere,  the  only  hemi- 
sphere in  which  there  is  any  large  amount  of  land  in  that 


RAINFALL  OF  THE   WORLD.  193 

belt,  has  a  small  annual  rainfall,  owing  in  part  to  the  fact 
that  cold  air  cannot  evaporate  moisture  rapidly.  We 
find  thus  that  northern  British  America,  Greenland,  and 
Siberia  have  a  rainfall  of  less  than  ten  inches  a  year,  and 
that  except  on  the  coast  of  both  North  America  and 
Eurasia,  as  far  south  as  the  trade-wind  belt,  the  rainfall 
is  small,  deserts  being  a  conspicuous  feature  in  the  inte- 
rior of  the  continents  on  the  leeward  side  of  the  mountain 
ranges.  The  same  thing  holds  true  in  southern  South 
America,  the  only  continent  in  the  southern  hemisphere 
that  reaches  really  into  the  cool  belt. 

In  the  warm  belts  we  find  a  large  amount  of  desert 
shown  in  the  southwestern  United  States,  in  the  Sa- 
hara, in  Arabia,  in  Persia,  and  in  the  Desert  of  Gobi 
in  northern  Tibet.  The  same  fact  is  shown  in  southern 
Argentina,  in  southwest  Africa,  and  in  Australia.  In 
the  hot  belts  we  find  the  regions  of  the  great  rainfalls  of 
the  world.  The  greatest  rainfall  known  is  at  Cherra 
Punjie,  India,  where  it  reaches  493  inches,  or  something 
over  40  feet  in  a  year.  A  fall  of  40.8  inches  occurred 
at  this  place  in  one  day,  on  June  14,  1876,  this  being 
almost  equal  to  the  amount  that  ordinarily  falls  during 
a  year  in  New  York  City,  which  usually  receives  about 
46  inches  a  year.  In  the  doldrum  belts  of  the  world 
the  rain  is  almost  daily  in  its  occurrence. 
13 


CHAPTER   XIX. 
CLIMATE   OF    THE   WORLD. 

Seasons. — In  any  of  the  climatic  or  heat  belts  the 
weather  changes,  in  a  general  way,  with  the  seasons,  and 
in  describing  the  climate  of  these  several  regions  it  is 
necessary  to  take  these  changes  into  consideration.  In 
the  cold  and  cool  belts  we  have  four  seasons,  the  more 
important  being,  of  course,  the  winters,  in  which  the 
region  is  cold,  and  the  summers,  when  the  countries  are 
warm,  reaching  at  certain  times,  for  a  few  days,  very 
high  temperatures.  In  the  warm  belts  we  have  cool 
winters  and  hot  summers;  and  in  the  hot  belts,  within 
which  the  heat  equator  lies  for  the  whole  year,  the  tem- 
perature is  always  hot.  In  this  latter  belt  and,  indeed, 
in  a  portion  of  the  warm  belts  we  have  two  seasons, 
brought  about  not  by  differences  of  temperature,  but  by 
differences  of  rainfall.  When  any  given  region  in  these 
areas  is  occupied  by  the  heat  equator,  we  have  the  rainy 
season,  and  when  it  is  not  occupied,  the  dry  season.  In 
the  northern  and  southern  portions  of  the  belt,  therefore, 
near  to  the  tropics,  there  are  two  seasons,  one  rainy  and 
one  dry,  the  rainy  occurring  when  the  sun  is  vertical,  and 
the  dry  when  the  sun  is  vertical  in  the  region  of  the  other 
tropic.  In  the  equatorial  region,  where  the  sun  is  verti- 
cal twice  a  year  (March  and  September),  instead  of  one 
we  have,  naturally,  two  rainy  seasons,  separated  by  two 
dry  seasons. 


SUMMARY.  195 

Summary. — In  the  hot  belt  there  is  in  general  a  high 
and  constant  temperature,  accompanied  by  a  heavy  rain- 
fall and  a  great  amount  of  moisture  in  the  air.  The 
climate  is  thus  uncomfortable  for  white  men,  owing  to 
the  excessive  moisture  and  the  high  temperatures,  and 
also  in  part  owing  to  the  fevers  that  are  found  to  be  so 
common  a  feature  of  the  torrid  regions.  Negroes  and 
certain  other  races  of  men  find  in  these  torrid  and,  to 
us,  uncomfortable  regions  the  very  conditions  favorable 
for  their  life,  and  thus  we  find  the  larger  part  of  these 
regions  occupied  by  primitive  peoples.  Over  the  low- 
lying  areas  the  temperatures  and  moisture  are  favorable 
for  the  development  of  luxuriant  vegetation,  like  that  of 
the  famous  tropical  forests  of  the  Amazon  and  of  Cen- 
tral America.  Associated  with  the  men  and  the  plants 
we  find  the  beautiful  tropical  birds,  and  the  heat-loving 
tropical  animals,  many  of  them  large  and  unwieldy,  like 
the  crocodile  and  hippopotamus. 

In  the  warm  belts  we  find,  as  we  have  seen,  two  sea- 
sons, the  wet  having  practically  all  the  discomforts  of  the 
tropics,  and  the  dry  being  comfortable  and  agreeable. 
In  this  region  we  have  the  savannas,  in  which  during  the 
rainy  season  there  is  a  luxuriance  of  vegetation,  particu- 
larly of  the  grasses,  which  dry  and  wither  in  the  follow- 
ing dry  seasons.  The  savanna  area  is  found  in  Brazil 
around  the  Orinoco,  in  Central  America,  in  the  Sudan, 
about  the  headwaters  of  the  Nile  in  Africa,  and  in 
northern  Australia. 

In  those  portions  of  the  warm  belt  that  are  excessively 
dry  we  have,  of  course,  the  characteristic  absence  of 
vegetation  of  the  desert,  with  its  further  scarcity  of 
population.  In  the  cool  belts  of  the  temperate  zones  we 
have  in  the  southern  portions  the  forests  and  the  grassy 


196  A   READER  IN   PHYSICAL  GEOGRAPHY. 

steppes,  illustrated  by  the  prairies  of  North  America  and 
the  forests  of  our  Eastern  States.  In  the  northern  por- 
tion we  find  abundant  forests,  mostly,  however,  of  conif- 
erous trees,  growing  smaller  and  smaller  as  they  ap- 


FIG.    83. — A  VIEW   IN    THE   TUNDRA   REGION   IN   ALASKA,    SHOWING 
CHARACTER    OF   VEGETATION. 

proach  the  polar  regions.  These  northern  regions  of 
the  cool  belt,  particularly  on  the  eastern  side  of  North 
America  and  Asia,  and  on  the  western  side  of  Europe, 
are  the  most  densely  populated  regions  of  the  world. 
This  is  in  part  due  to  the  favorable,  though  changeable 


SUMMARY.  197 

climate,  to  the  rainfall,  and  to  the  conditions  that  make 
the  growth  of  cereals  and  other  food-giving  crops  easy 
and  successful. 

In  the  northern  polar  regions  we  have  the  tundra  (see 
Fig.  83),  known  in  North  America  as  the  barren  grounds. 
Crops  will  not  grow  here;  the  principal  forms  of  vegeta- 
tion being  the  mosses  and  lichens  which  almost  cover  the 
ground  during  the  short  summer.  This  tundra  region  is, 
of  course,  frozen  during  a  large  part  of  the  year;  and  in 
the  extreme  north,  nothing  but  snow  and  ice  can  be  seen. 
Hence  these  regions,  like  the  deserts  of  the  warm  belt, 
are  practically  without  any  inhabitants,  a  very  large  pro- 
portion of  the  area  having  less  than  one  inhabitant  to  the 
square  mile,  whereas  in  certain  portions  of  China  and 
India  there  are  approximately  500  inhabitants  to  the 
square  mile. 

The  northern  temperate  region,  inasmuch  as  it  con- 
tains a  larger  part  of  the  healthful,  inhabitable  part  of 
the  world,  is  therefore  the  region  occupied  by  the  most 
dense  population.  It  is  also  the  region  where  the  con- 
ditions of  climate  tend  to  make  a  man  active  rather  than 
inactive,  and  in  which,  therefore,  we  find  the  progressive 
nations  of  the  world,  as  is  perhaps  best  shown  by  noting 
the  position  of  the  United  States  and  southern  Canada, 
of  England,  France,  and  Germany,  and  of  Japan,  in  ref- 
erence to  the  heat  belts. 


OTHER  IMPORTANT  PHYSICAL 
FEATURES  INFLUENCING  MAN. 

CHAPTER    XX. 
SOILS. 

IT  has  sometimes  been  said  that,  were  a  man  from 
the  planet  Mars  to  land  on  the  Earth,  with  the  thought 
of  making  his  home  here,  he  would  at  once  ask  several 
practical  questions  in  reference  to  the  parts  of  the  earth 
in  which  he  could  live  without  too  great  difficulty  or 
labor.  Were  such  a  thing  possible,  such  a  man  would 
undoubtedly  come  to  us  with  an  understanding  of  the 
way  a  planet  is  divided  into  great  climatic  belts,  habitable 
or  uninhabitable  according  to  the  distribution  of  tem- 
perature over  the  planet.  With  this  information  in 
mind,  he  would  undoubtedly  first  ask  as  to  the  character 
of  the  country  in  each  of  the  climatic  divisions,  for  he 
would  want  to  know,  for  instance,  whether  there  were 
mountains  in  the  torrid  portions  of  the  earth  that  would 
enable  him  to  find  temperate  conditions  there;  he  would 
want  to  know  something  about  the  topography  of  the 
larger  temperate  belts  of  the  earth,  that  he  might  be 
informed  whether  the  country  were  available  for  agricul- 
ture, or  manufacturing,  or  some  other  industry. 

A  knowledge  of  the  climate,  then,  would  enable  him 
to  find  some  large  area  in  the  world  agreeable  to  him; 


SOILS.  199 

a  knowledge  of  the  topography  of  the  region  would  per- 
haps enable  him  to  choose  some  particular  locality  in  that 
area.  In  order  to  be  able  to  choose  his  home  with  exact- 
ness, he  would,  however,  have  to  find  out  a  number  of 
other  matters.  He  would  want  to  know  something  of 
the  soils;  something  as  to  the  supply  of  water;  as  to  the 
means  of  defence;  the  ease  of  transportation;  as  to 
whether  there  were  natural  power,  and  natural  products 
that  would  give  him  the  materials  for  a  sheltering  house, 
for  his  necessary  utensils,  for  his  clothing,  and  for  his  food. 
These  are  some  of  the  other  matters,  all  of  them  more  or 
less  geographical  in  their  distribution  or  character,  that 
help  determine  whether  men  can  live  in  different  parts  of 
the  world,  and  if  they  can  live  there,  their  occupations 
and  customs. 

In  any  region  the  character  of  the  topography  has  a 
great  influence  upon  the  distribution  and  the  character 
of  the  life  throughout  the  country.  This  applies,  of 
course,  more  particularly  to  the  temperate  region,  in 
which  the  progressive  nations  of  the  world  live.  The 
highlands  we  found  to  be  regions  of  steep  slope,  of  cooler 
climate,  usually  of  thin  soil,  and  in  some  cases  covered 
continually  with  snow;  their  windward  sides  wet  and 
perhaps  habitable,  their  leeward  sides  dry  and  barren. 
From  their  height  and  their  extent  they  are  apt  to 
be  great  barriers,  making  migration  and  cross-country 
travelling  difficult.  Thus,  as  a  rule,  highlands  are  iso- 
lated regions,  except  where  they  contain  minerals,  or 
bear  forests,  of  profit  to  man. 

In  striking  contrast  to  the  highlands,  we  found  that 
lowlands  were  generally  favorable  to  life.  Their  gentle 
slope,  their  deeper  and  richer  soil,  their  abundant  water 
supply,  if  situated  favorably  as  to  climate,  and,  in  gen- 


2OO  A   READER  IN   PHYSICAL  GEOGRAPHY. 

eral,  their  larger  and  more  navigable  rivers  are  some 
of  the  features  which  make  these  regions  desirable  for 
homes.  As  we  found  the  windward  side  of  highlands 
habitable,  so  we  find  that  lowlands  on  the  windward  side 
of  continents  are  generally  favorable  to  life;  whereas 
those  in  the  interior,  or  in  the  trade-wind  belt,  as  in  the 
case  of  the  Sahara,  may  be  anything  but  habitable. 

In  any  region  we  found  the  character  of  the  slopes  im- 
portant. Where  the  slopes  are  steep,  the  soil  is  apt  to 
be  thin,  and  grazing  and  lumbering,  rather  than  agricul- 
ture, are  the  occupations.  The  steepest  slopes  are  given 
over  to  waste  regions,  perhaps  occupied  only  by  climbing 
animals  and  stunted  trees.  The  streams  of  such  a  region 
are  swift  and  small,  and  the  water  that  falls  will  run  off 
at  once,  perhaps  swelling  the  streams  to  a  flood. 

In  the  regions  of  gentle  slope  we  found  other  occu- 
pations, and  more  particularly  those  of  agriculture  and 
manufacturing,  to  be  the  most  successful,  owing  in  part 
to  the  depth  of  soil,  the  abundance  of  water,  and  to 
the  ease  of  cross-country  travelling.  In  the  gentle  slopes 
of  the  great  plains  and  prairies  of  the  world  were  formerly 
to  be  found  the  nomadic  and  perhaps  warlike  tribes  of 
primitive  people,  which  have  now,  at  least  in  North 
America,  so  largely  given  way  to  the  more  advanced 
races. 

Agriculture  is  the  most  important  industry  of  the 
world;  for  as  all  men  must  eat  *in  order  to  live,  it  is 
evidently  of  the  utmost  importance  that  food  be  pro- 
vided. Men  live  either  on  the  vegetable  products  of 
the  soil,  or  the  flesh  of  animals  that  have  lived  on  these 
products.  The  conditions,  therefore,  that  make  agri- 
culture possible  in  a  region  are  very  important.  The 
character  of  the  soil,  then,  is  the  third,  perhaps,  in  impor- 


KINDS   OF  SOILS.  2OI 

tance  of  the  several  things  that  influence  man  in  his 
distribution. 

Soils  are  made  mostly  from  the  weathered  and  decayed 
rocks  of  the  earth,  although  all  valuable  soils  contain  a 
certain  amount  of  decayed  animal  or  vegetable  matter. 
Any  weathering  rock-surface  shows  us  soil  in  the  mak- 
ing, and  the  mosses  and  lichens  that  grow  perhaps  on  a 
strong  rock  surface  that  has  weathered  but  little  aid  in 
the  deepening  and  enriching  of  the  soil.  Soils  are  not 
of  value,  however,  until  they  are  sufficiently  deep  to  sup- 
port the  larger  crops. 

Kinds  of  Soils. — The  soils  of  the  world  may  roughly 
be  divided  into  two  great  groups,  according  to  the  way 
the  materials  of  that  soil  have  been  accumulated.  We 
may  have  a  soil  which  has  been  formed  by  the  decaying 
of  the  rock  on  which  it  lies,  or  we  may  have  a  soil  the 
particles  of  which  have  been  brought  from  very  many 
places,  and  perhaps  from  a  great  distance.  Of  the  latter 
group  the  more  important  are  the  soils  carried  along  and 
finally  deposited  either  by  the  rivers,  the  wind,  or  by 
moving  ice.  In  the  northern  United  States  the  latter 
class  are  the  most  important,  for  all  the  land  of  the  area 
formerly  covered  by  the  ice,  which  we  have  already  out- 
lined, is  covered  by  soils  brought  to  their  present  posi- 
tion by  the  great  ice-sheet.  In  some  cases  the  soils 
are  thick,  and  in  some  cases  they  are  very  thin.  Their 
richness  depends  upon  their  depth,  and  also  upon 
whether  they  were  deposited  by  the  ice  itself,  when  they 
are  more  or  less  clayey  and  fertile,  or  by  the  water  which 
ran  from  beneath  the  ice,  when  they  are  usually  sandy. 
Of  this  latter  character  are  the  soils  of  southern  Long 
Island  and  Staten  Island ;  the  soils  found  among  the 
ledges  on  the  heights  and  in  the  parks  of  Greater  New 


2O2  A   READER  IN   PHYSICAL  GEOGRAPHY.  • 

York,  and  on  the  higher  hilltops  of  New  England,  are  ice- 
brought  clayey  soils,  and  are  extremely  rich,  although 
they  often  cover  but  a  small  area. 

The  most  important  group  of  soils,  taking  the  world  as 
a  whole,  however,  is  perhaps  the  river-made  soil,  such  as 
is  found  in  the  great  alluvial  plains  of  the  world,  and 
along  the  lower  courses  of  most  rivers.  In  order  for  a 
soil  to  be  valuable,  it  must  be  made  of  fine  materials, 
and  should  contain  just  as  many  different  kinds  of  mate- 
rials as  possible.  River  and  ice  made  soils  are  rich  for 
both  of  these  reasons.  In  each  case  the  materials  are 
very  fine,  and  further,  there  are  many  different  kinds  of 
rock  in  each  soil,  because  the  rivers  or  ice  bring  soil 
materials  from  so  many  different  rock  ledges  and  hill- 
sides up-stream. 

The  third  kind  of  soil,  made  from  materials  brought 
from  a  great  distance,  and  from  very  many  places,  is  that 
accumulated  by  the  wind.  In  the  sand-dunes  of  our  sea- 
shores and  deserts  we  have  excellent  examples  of  such 
sand-accumulations,  usually,  however,  not  available  for 
plant  life,  owing  to  their  sandy  character,  and  to  the  fact 
that  they  are  so  porous  that  water  runs  through  them 
easily,  and  is  not  retained  for  the  use  of  the  plant.  The 
loess  deposits  we  have  already  mentioned  are,  however, 
much  more  fertile. 

Outside  of  the  regions  where  the  ice,  running  water, 
or  the  wind  has  deposited  any  materials,  which,  of 
course,  include  the  larger  part  of  the  earth,  we  have 
soils  made  entirely  of  the  weathering  of  the  underlying 
rocks,  and  hence  depending  for  their  character  on  the 
kind  of  rocks  from  which  they  have  been  formed.  If 
those  rocks  are  strong  and  contain  a  large  amount  of 
quartz,  such  as  sandstone,  the  soil  formed  therefrom  will 


KINDS  OF  SOILS.  203 

probably  be  poor,  as  the  rock  materials  are  not  very 
easily  dissolved.  If,  on  the  other  hand,  the  rock  is 
easily  eroded,  and  particularly  if  it  contain  lime,  as  do 
limestones,  the  soil  will  be  rich.  Soils  formed  by  the 
weathering  and  rusting  of  the  rocks  have  a  rusty  red 
color,  varying  from  a  reddish  yellow  to  a  deep  dark  crim- 
son. Limestone  soils  are,  perhaps,  the  best  of  the  great 
group  of  soils  made  in  this  way,  the  limestone  soils  of 
the  Shenandoah  and  Tennessee  valleys  being  famous  for 
their  fertility  and  richness.  Soils  formed  from  volcanic 
rocks,  or  from  granites,  are  usually  rich,  although  it 
should  be  noted  that  it  takes  a  very  long  time  for  rocks 
of  this  class  to  weather  into  soils.  Yet,  as  a  matter  of 
fact,  there  are  areas  of  the  world  in  which  the  granite 
soils  are  several  hundred  feet  deep ;  that  is,  where  one 
would  have  to  dig  down  into  the  earth  for  perhaps  four 
hundred  feet  to  reach  any  solid,  unweathered  rock. 

In  almost  any  exposure  of  soil,  brought  to  light  by 
cutting  into  a  decomposing  rock  hill,  for  instance,  we 
find  a  certain  series  of  soil  characteristics  in  a  very 
definite  order,  as  we  descend  into  the  earth.  At  the  top 
there  are  usually  a  few  inches  of  dark,  perhaps  almost 
black  soil,  of  a  very  fine  character,  containing  a  large 
amount  of  decomposed  plant  materials;  beneath  this  we 
find  the  plant  remains  less  conspicuous,  and  the  parti- 
cles of  soil  larger,  the  rusty  color  standing  out  more 
prominently  in  consequence.  Perhaps  at  a  depth  of  ten 
or  twelve  feet  we  may  be  able  to  see  that  the  rock  was 
once  a  continuous  mass,  afterwards  broken  into  great 
blocks,  the  edges  and  sides  of  which  have  weathered  and 
rusted,  until  now  we  have  a  series  of  rounded  boulders, 
between  which  lie  the  finer  soil  particles.  At  some  dis- 
tance below  this  would  come  the  solid  rock. 


204  A  READER  IN   PHYSICAL  GEOGRAPHY. 

Fertility  of  Soils. — The  fertility  of  any  soil  is  deter- 
mined  by  the  kind  of  materials  of  which  it  is  made  and 
by  the  fineness  of  the  particles.  Whether  a  soil  can  be 
used  or  not  depends  upon  certain  other  things,  primarily 
upon  its  position  in  the  heat  belts.  The  soils  of  the 
Mackenzie  River  are  naturally  just  as  rich  as  those  of 
any  other  great  river  valley,  but  they  are  in  a  region  too 
cold  to  be  of  any  value  for  agriculture.  The  soils  of  the 
Amazon  are  as  rich  as  those  of  the  Nile,  or  the  Euphrates, 
or  the  Yangtse-kiang,  but  they  occur  in  a  region  too  hot 
and  too  wet  to  be  available  for  agriculture,  though  they 
support  a  most  luxuriant  tropical  vegetation.  In  con- 
trast to  this  we  have  pur  own  Mississippi  River,  flowing 
from  a  cold  into  a  warm,  but  not  a  hot  region,  with  its 
rich  alluvial  soil  in  a  favorable  climate. 

Another  question  that  determines  whether  a  soil  will 
be  of  value  is,  of  course,  the  presence  of  water.  As  has 
already  been  suggested,  a  rainfall  of  eighteen  or  twenty 
inches  a  year  is  necessary  for  agriculture.  If  the  rainfall 
is  but  a  little  less  than  that,  giving  us  a  semi-arid  climate, 
crops  can,  perhaps,  be  grown  once  in  every  few  years;  if 
much  less  than  this,  as  in  deserts,  agriculture  is  impossi- 
ble unless  the  region  be  irrigated,  or  artificially  watered. 

Certain  crops  take  certain  products  from  the  soil,  and 
others  take  other  materials;  therefore  a  farmer  does  not 
plant  potatoes  or  corn  on  the  same  area  year  after  year, 
but  perhaps  plants  corn  one  year  and  potatoes  the  next, 
and  then  allows  grass  to  grow  for  a  few  years,  or,  as  we 
say,  he  rotates  his  crops,  in  order  to  make  use  of  all  the 
different  contents  of  the  soil  without  using  up  all  of  any 
particular  thing.  In  this  way  soils  may  be  kept  from 
wearing  out,  and  may  be  of  service  for  the  raising  of 
crops  year  after  year.  A  successful  farmer,  however, 


FERTILITY   OF   SOILS.  2O5 

does  not  depend  upon  his  crop  getting  from  the  soil  all 
the  material  it  needs,  but  adds  to  the  soil  a  certain 
amount  of  fertilizer,  which  makes  the  crops  grow  more 
rapidly  and  saves  the  soil  from  being  made  too  poor  by 
the  growth  of  the  plants. 


CHAPTER    XXI. 

WATER   SUPPLY. 

THE  water  supply  is  another  of  the  very  important 
features  that  determines  whether  a  region  will  be  hab- 
itable or  not.  Not  only  must  there  be  a  continual  sup- 
ply of  water  in  the  soil  for  the  use  of  plants,  but  there 
must  be  surface  water  for  drinking  and  bathing  purposes, 
for  animals  and  men.  That  water  must  also  be  free 
from  impurities  which  make  it  distasteful  or  unfit  for  use. 
In  some  parts  of  the  world  there  is  plenty  of  water,  but 
it  is  so  full  of  certain  minerals  dissolved  from  the  soil  that 
in  some  cases  it  is  poisonous  both  to  plants  and  animals. 
In  other  cases  the  water  may  be  full  of  minerals,  making 
it  disagreeable  for  every-day  use,  but  of  value  for  invalids ; 
such,  for  instance,  is  the  sulphur  water  at  Avon  Springs, 
in  central  New  York,  and  the  many  different  mineral 
waters,  some  cold  and  some  warm,  found  at  Saratoga, 
New  York. 

In  any  region  in  which  the  rainfall  is  as  great  as  it  is 
in  the  eastern  United  States,  there  is  plenty  of  water  for 
most  purposes,  the  amount,  however,  varying  with  the 
season,  and  somewhat  with  the  ability  of  the  rocks  under- 
neath the  soil  to  keep  the  water  from  soaking  through 
and  running  to  the  rivers  too  rapidly.  A  clay  rock  will 
retain  more  water  than  a  sand  rock,  and  therefore  usually 
furnishes  a  better  water  supply,  without  difficulty.  The 
amount  of  water  in  the  soil  depends  largely  upon  whether 
the  wa^er  of  a  rain  runs  immediately  to  the  ocean  through 


SPRINGS  AND   WELLS.  2O/ 

the  rivers,  or  whether  it  soaks  into  the  ground,  and 
moves  toward  the  sea  slowly,  thus  lasting  a  long  time. 
In  regions  where  the  hill  slopes  are  bare  of  trees,  par- 
ticularly around  the  headwaters  of  streams,  the  larger 
part  of  the  water  that  falls  in  any  storm  runs  off  imme- 
diately, producing  freshets  in  the  streams,  followed  by 
a  period  of  low  water,  or  a  drouth.  Hence  the  advan- 
tage of  keeping  a  certain  part  of  a  region  forested,  for  in 
a  forest-covered  area  the  soft,  spongy  mat  of  decaying 
leaves  and  wood  lying  beneath  the  trees  holds  the  mois- 
ture, and  is  always  damp.  That  water  soaks  slowly 
through  the  rocks  is  also  shown  by  the  fact  that  in  a  for- 
ested area  we  find  but  little  erosion  of  the  country  by 
streams;  there  are  few  tributaries  to  any  large  stream, 
and  but  little  evidence  of  stream  work. 

Springs  and  Wells. — The  underground  water  must,  of 
course,  be  brought  to  the  surface  to  be  of  use,  at  least 
for  those  people  who  occupy  land  on  the  hillsides,  and 
away  from  the  river  valleys.  In  the  upper  portion  of 
river  valleys  a  part  of  the  water  may  easily  be  made  to 
turn  off  into  a  little  trench  or  ditch,  and  run  along  the 
side  of  the  hills  at  a  more  gentle  slope  than  the  main 
stream  follows  in  the  valley  below.  Thus  the  water  may 
be  brought  out  upon  the  land  of  the  hillside  farms  and 
used  there,  either  to  water  the  land  or  to  turn  wheels  of 
mills.  This  is  the  method  of  securing  water  frequently 
employed  in  those  parts  of  our  arid  Western  plains  where 
there  are  few  large  rivers,  and  where  irrigation  is  neces- 
sary to  produce  crops  on  the  slopes.  (See  Fig.  84.)  The 
success  of  this  means  of  watering  the  land  is  very  evi- 
dent in  an  irrigated  region,  where  the  part  that  has 
been  watered  is  beautifully  green,  while  the  area,  per- 
haps but  a  few  feet  away,  which  has  not  been  supplied 


208  •  A   READER   IN   PHYSICAL  GEOGRAPHY. 

with  water  is  dry,  and  as  barren  as  a  city  street.     (See 
Fig.  85.) 

The  most  common  way  in  which  underground  water 
is  brought  to  the  surface  is  through  natural  springs. 
Springs  occur  wherever  some  underlying  mass  of  rock, 
through  which  the  water  cannot  easily  soak,  comes  to 


FIG.    84. — AN     IRRIGATION     DITCH     IN     CALIFORNIA,     BUILT     ALONG    A 
HILLSIDE    WITH    A    GENTILE    SLOPE. 

the  surface.  The  water  which  has  soaked  down  to  the 
rock  surface  follows  it,  and  appears  at  the  surface  of  the 
land  when  the  rock  appears.  (See  Fig.  86.)  In  New 
England  and  certain  parts  of  New  York,  where  the  soils 
are  thin  and  where  the  underlying  hard  rock  is  not  easily 
penetrated 'by  the  water,  springs  formed  in  this  way  are 
very  numerous.  In  the  hills  of  Massachusetts  and  Con- 
necticut the  roadside  springs,  which  have  been  cleaned 


SPRINGS  AND   WELLS.  200 

and  fitted  up  for  the  use  of  travellers,  either  animals  or 
men,  make  travelling  a  pleasure  and  a  comfort.  Springs 
are  also  important  as  being  the  sources  of  rivers,  each 
spring  or  wet  spot  on  a  hillside  or  in  a  valley  being  one 
of  the  perhaps  thousands  of  little  feeders  that  supply 
the  stream.  Rivers  cannot  therefore  be  said  to  have  but 
one  source.  They  have  too  many  to  count. 

Outside  of  large  cities,  the  customary  way  of  getting 


FIG.    85. — AN   IRRIGATED    TOWN    IN    UTAH.       THE    DISTANT   HILLS    ARE    IN 
THE  UNIRRIGATED    REGION    AND    VERY    BARREN. 

underground  water  for  house  and  farm  use  is  through 
wells.  A  well  is  a  hole  dug  down  into  the  earth  deep 
enough  to  reach  some  of  the  water  that  is  trickling 
through  the  soil.  The  water  is  then  raised  or  pumped 
to  the  surface  and  used.  In  former  times  many  of  the 
villages  of  New  England  had  but  one  well,  to  which  all 
the  inhabitants  went  for  their  drinking  water,  driving 
their  cattle  to  the  more  distant  streams.  In  some  places 
we  still  find  such  a  town  well,  located  in  the  centre  of 
14 


2IO 


A   READER  IN   PHYSICAL  GEOGRAPHY. 


the  village,  convenient  to  every  one,  and  usually  known 
as  the  town  pump.  In  certain  parts  of  our  Southern 
States  we  find  the  little  villages  or  settlements,  perhaps 
of  only  two  or  three  houses,  located  around  a  good 


FIG.    86. — SPRING   HIGH   UP   ON   MT.    MAZAMA,    OREGON. 


spring.  In  such  cases  it  was  the  presence  of  the  spring 
that  determined  the  location  of  the  little  town,  while  in 
New  England  the  town  pump  was  placed  after  the  town 
was  started,  the  town  being  determined  in  its  position  by 
some  other  cause. 


SPRINGS  AND   WELLS. 


211 


Where  large  supplies  of  water  need  to  be  secured  from 
a  well,  the  water  is  pumped  out  by  steam,  or  by  the 
wind,  as  may  be  seen  on  many  of  the  large  farms  of  New 
York  and  the  Central  States,  where  windmills  supply 
water  for  large  herds  of  cattle,  and  running  water  for  the 
many  buildings  of  the  farms.  In  the  ranching  country 


FIG.     87. — A    FLOODED    RIVER    VALLEY    FORMING    A    RESERVOIR    IN 
CONNECTICUT. 

of  our  Western  plains,  where  trees  are  absent,  we  some- 
times see  occasional  windmills  that  supply  water  for  the 
cattle,  the  mills  rising  to  a  height  of  but  a  few  feet, 
being,  however,  very  conspicuous  objects  in  the  land- 
scape, and  visible  for  miles  in  every  direction. 

In  still  other  cases,  the  supplies  of  underground  water 
are  so  very  deep  beneath  the  surface  of  the  earth  that 
what  are  known  as  artesian  wells  have  to  be  dug.  (See 


212  A   READER   IN   PHYSICAL   GEOGRAPHY. 

Fig.  1 8.)  An  artesian  well  is  a  hole  dug  or  bored  into 
the  earth,  possibly  for  several  hundred  feet,  until  finally 
a  supply  of  water  is  reached,  which  rises  through  the 
hole  perhaps  to  the  very  surface  of  the  earth,  or  at  least 
high  enough  to  be  pumped  out.  Artesian  wells  make 
possible  the  water  supply  of  cities  and  summer  resorts 
built  on  sandy  beaches  far  from  land,  such  as  Atlantic 
City,  New  Jersey,  for  instance.  In  some  cases  the  water 
of  rivers  is  accumulated  in  a  natural  or  artificial  lake, 
making  a  great  reservoir,  the  contents  of  which  can  be 
used  as  one  wishes.  (See  Fig.  87.)  The  water  from  such 
reservoirs  is  often  carried  through  pipes  for  long  dis- 
tances, and  supplied  to  large  cities,  as  the  water  from 
Croton  River  is  carried  to  New  York  City. 

In  the  early  exploration  of  this  country  the  presence 
of  accessible  water  determined  the  location  of  towns  in 
a  good  many  cases,  and  in  still  more  cases  it  was  the 
presence  or  absence  of  water  that  separated  the  region 
first  occupied  from  that  occupied  at  a  later  date.  At  the 
present  time  even,  the  cross-country  trails  in  the  arid 
plains  have  all  been  chosen  and  determined  in  their  direc- 
tion by  the  presence  of  little  pools  of  water  that  will  fur- 
nish a  supply  sufficient  for  the  traveller.  A  traveller  not 
only  follows  the  trail  which  takes  him  by  the  water,  but, 
when  it  is  possible  to  do  so,  arranges  his  journey  in  such 
a  way  that  he  will  stop  at  night  where  this  necessary  is 
to  be  found.  When  he  crosses  a  long  stretch  of  country 
where  no  water  can  be  obtained,  he  must  carry  a  supply 
with  him.  As  a  matter  of  fact,  the  keg  or  canteen  of 
water  is  as  important  a  part  of  the  traveller's  outfit  in  an 
arid  country  as  is  the  horse  that  carries  him. 


CHAPTER   XXII. 
DEFENCE   AND    NATURAL   PRODUCTS. 

A  NEW  settler,  having  found  a  land  in  which  _the 
climate,  topography,  good  soils,  and  a  water  supply 
favored  his  building  a  home,  would  next  have  to  con- 
sider the  means  of  defence  from  his  natural  enemies, 
whether  they  be  animals  or  men,  and  he  would  have 
to  take  advantage  of  all  the  natural  features  in  the 
region  that  would  make  the  defence  easy.  In  the  dif- 
ferent parts  of  the  world,  particularly  among  primitive 
peoples,  we  find  the  life  of  the  inhabitants  of  a  country 
very  largely  influenced  by  the  manner  in  which  they 
defend  themselves.  In  some  ways  the  most  interest- 
ing peoples,  from  the  standpoint  of  defence,  are  the 
wandering  or  nomadic  tribes  of  great  plains,  such  as  the 
Arabs  of  the  deserts  of  Arabia  and  Sahara,  and  our 
American  Indians,  who  formerly  occupied  the  great 
prairies.  Such  peoples  find  on  plains  the  food  for  their 
cattle  and  horses  and  all  the  necessaries  of  life.  They 
live  a  life  that  allows  them  to  move  quickly  from  place 
to  place,  as  their  flocks  have  to  move  to  new  feeding 
grounds,  and,  further,  that  allows  them  to  flee  quickly  if 
they  are  suddenly  attacked  by  an  enemy  superior  to  them 
in  numbers. 

Nomadic  people  depend  largely  for  their  defence  upon 
the  fact  that  they  can  see  their  enemies  at  a  great 
distance,  owing  to  the  character  of  the  country,  thus 
having  plenty  of  opportunity  for  flight,  if  flight  is 


214  A   READER   IN   PHYSICAL   GEOGRAPHY. 

necessary.  From  the  habit  of  being  continually  on  the 
watch  for  anything  moving  in  the  landscape,  and  from 
long  training,  they  have  become  able  to  recognize  an 
enemy  when  he  is  far  away.  Thus  peoples  like  our 
American  Indians  have  gained  a  reputation  for  wonder- 
ful sight,  whereas,  as  a  matter  of  fact,  they  see  no  more 
clearly  than  a  white  man  would  see.  They  have,  how- 
ever, trained  themselves  to  know  a  cloud  of  dust  raised 
by  an  enemy  or  by  horses  from  a  wind  cloud,  when  the 
white  man  might  be  unable  to  distinguish  between  them. 
The  people  who  live  in  mountains,  however,  have,  per- 
haps made  the  best  use  of  their  natural  means  of  defence. 
Living  in  the  lower  valleys,  or  on  the  hill  slopes  border- 
ing the  streams,  enemies  can  come  upon  them  in  but  few 
directions,  either  up  the  valley  or  down  the  slopes  from 
the  head  of  the  river,  having  come  from  a  neighboring 
valley  over  the  pass  across  the  divide.  Thus  the  people 
can  defend  themselves  by  defending  the  inlets  to  their 
home,  and  a  few  sentinels  on  the  hilltops  can  very  readily 
warn  all  the  inhabitants  of  an  approaching  stranger  in 
plenty  of  time  for  any  necessary  preparation  to  resist  an 
enemy.  Mountain  peoples  living  in  isolated  villages  in 
single  valleys  have  but  little  opportunity  to  mingle  with 
their  neighbors,  and  come  to  have  many  peculiar  ways, 
perhaps  very  different  from  those  of  their  neighbors  in 
the  next  valley.  We  see  this  development  of  isolated 
communities  in  separate  valleys  in  certain  parts  of  our 
Southern  States,  as,  for  instance,  in  Kentucky  and  Ten- 
nessee, where  the  people  living  in  the  flat-bottomed  river 
valleys  that  run  back  along  the  streams  between  the  high 
but  perhaps  narrow  ridges  on  either  side,  being  isolated 
in  these  small  coves,  know  but  little  of  the  outside  world 
or  their  neighbors.  Such  conditions  of  country  and  the 


DEFENCE  AND   NATURAL   PRODUCTS. 


215 


manner  of  life  favor  the  continuance  of  the  family  feuds, 
of  perpetual  quarrels,  for  which  this  region  is  notorious. 
Another  way  in  which  primitive  peoples  defend  them- 
selves is  by  building  their  houses  in  a  spot  naturally  pro- 
tected and  somewhat  inaccessible.  In  Arizona  and  New 
Mexico  there  are  great  numbers  of  so-called  cliff  houses 


FIG.    OS. — A   CLIFF    HOUSE    IN   A   NEW    MEXICO    CANON    FAR     ABOVE    THE 
VALLEY   FLOOR. 

built  up  on  the  sides  of  the  steep-walled  valleys  in  little 
niches  under  an  overhanging  ledge  of  rock.  (See  Fig.  88.) 
In  such  a  case,  attack  is  impossible  from  above,  and  diffi- 
cult from  below,  as  perhaps  the  paths  leading  up  to  the 
houses  are  very  few  and  very  difficult  to  climb.  Cliff 
houses  still  remain  in  this  region,  showing  the  former 


2l6  A   READER   IN   PHYSICAL   GEOGRAPHY. 

presence  of  great  numbers  of  people,  but  the  people 
have  all  gone. 

In  certain  parts  of  China,  however,  we  do  have  cliff 
dwellers  at  the  present  time,  where  the  people  have  dug 
little  caves  in  the  sides  of  the  steep  cliffs,  as  a  swallow 
digs  a  hole  into  a  sand-bank.  A  traveller  going  through 
such  a  region  might  think  the  country  uninhabited, 
seeing  not  a  soul;  and  yet  perhaps  the  country  contains 
thousands  of  people,  all  of  whom  have  fled  into  their 
little  burrows  on  the  sight  of  a  supposed  enemy,  very 
much  as  rabbits  disappear  when  they  see  a  dog. 

Primitive  peoples  sometimes  protect  themselves,  too, 
by  building  their  homes  out  in  lakes,  where  they  cannot 
readily  be  reached  from  the  shore.  Formerly  large  num- 
bers of  these  lake  dwellers  lived  in  Switzerland,  and  in 
Lake  Titicaca  in  South  America,  and  now  such  lake 
houses  are  known  in  many  places,  among  others  in  the 
Philippines. 

In  most  regions  of  the  world,  however,  natural  protec- 
tion is  not  readily  afforded ;  therefore  the  first  duty  of 
the  early  settler,  as  was  illustrated  in  the  settlement  of 
New  England  and  Virginia,  is  the  building  of  the  stock- 
ade, or  walled  town,  and  the  establishing  of  a  body  of 
defenders  known  as  the  militia.  The  stockade  was  in 
reality  a  wooden  fence  that,  for  a  time  at  least,  kept  off 
the  Indians,  in  case  of  attack,  and  enabled  the  early  set- 
tlers to  protect  their  flocks  and  herds  from  the  attacks  of 
wild  animals  at  night.  We  see  the  same  principle  of  the 
walled  town  in  the  building  of  a  fort  on  the  highest  and 
most  easily  protected  spot  in  many  towns,  to  which  the 
inhabitants  can  flee  in  time  of  danger,  and  again  in  the 
ancient  and  famous  castles  of  Europe,  in  which  the  master 
lived,  and  around  which,  in  the  time  of  trouble,  he  gath- 


DEFENCE  AND   NATURAL   PRODUCTS. 


ered  all  the  people  dependent  upon  him.  We  see,  again, 
the  same  means  of  defence  adopted  in  our  arid  Western 
plains,  where  walled  towns,  large  enough  to  hold  in  some 
cases  a  great  many  hundreds  of  people,  were  once  built 
either  on  some  isolated  hilltop,  as  are  the  present  villages 
of  the  Moki  and  Zufii  Indians  in  Arizona,  or  perhaps  out 
in  the  open  plain,  as  is  illustrated  by  many  of  the  ancient 
pueblo  villages  now,  like  the  cliff  houses,  deserted  by 
their  former  inhabitants.  (See  Fig.  89.) 


.,^:,,       •  ;- 


FIG.  89. — RUINS  OF  A  PUEBLO  TOWN  IN  NEW  MEXICO.  AN  INTERMIT- 
TENT STREAM  RUNS  CLOSE  BESIDE  THE  PUEBLO  IN  THE  CAffON 
SHOWN. 

A  region  that  will  progress  the  most  rapidly,  other  con- 
ditions being  favorable,  is  that  region  in  which  the  en- 
ergies of  the  people  can  be  devoted  to  their  industries 
with  the  least  thought  of  defence.  Towns  and  first  settle- 
ments are  usually  placed,  if  possible,  in  the  most  readily 
defended  position*  The  early  settlers  who  came  to  Vir- 
ginia were  warned  before  they  came,  to  build  their  houses 
in  an  open  place,  sufficiently  distant  from  the  woods, 
so  that  the  Indians  could  neither  get  together  without 
being  seen,  nor  throw  arrows  or  other  implements  into 


218  A   READER   IN   PHYSICAL  GEOGRAPHY. 

the  town  from  behind  some  natural  shelter.  Thus  clear- 
ings were  made,  and  the  wood  of  the  cut  trees  was  used 
in  making  the  houses  and  the  stockades.  In  our  West- 
ern plains  the  early  settlers  could  not  readily  protect 
themselves,  and  hence  settlement  was  slow  and  danger- 
ous, and  the  Indian  inhabitants  were  a  continual  menace 
to  the  unprotected  people  until  within  a  very  few  years. 

Natural  Products. — Having  established  a  home  and 
gained  the  necessary  means  for  life  from  the  soil,  the 
new  inhabitant  naturally  looks  about  him  to  see  what 
else  the  region  affords  that  will  aid  in  making  his  life  more 
successful.  In  modern  times  it  is  often  the  natural  prod- 
ucts of  the  earth  that  lead  men  into  new  regions,  as 
recently  men  have  been  attracted  to  the  gold  fields  of 
Alaska.  But  in  early  times  the  use  of  the  natural  prod- 
ucts very  largely  came  after  the  settlement  of  the  region. 
Man  must  have  not  only  food,  but  shelter  and  clothing, 
and  therefore  a  region  will  develop  most  rapidly  in  which 
the  best  opportunity  is  afforded  for  the  easy  getting  of 
these  necessaries  of  life. 

The  American  Indian  used  skin  or  stone,  or  possibly 
clay,  to  make  his  home,  gathering  the  skins  from  the 
animals  of  the  chase,  and  using  clay  or  stone  only  in  the 
more  permanent  winter  home,  as  do  the  Navaho  Indians 
at  the  present  time.  White  men,  as  a  rule,  use  wood 
for  their  homes,  and  the  opening  up  of  some  regions  is 
largely  hampered  by  the  absence  of  forests  capable  of 
furnishing  wood  for  building  and  for  utensils.  The  most 
important  of  the  natural  products  that  are  at  present 
gathered  from  the  earth  for  building  purposes  is  iron. 
This  is  now  one  of  the  most  used  minerals  of  the  world, 
not  only  for  building  purposes,  but  in  all  the  arts  and 
industries. 


NATURAL  PRODUCTS.  2IQ 

Man  gathers  his  materials  for  clothing  very  largely 
from  the  skins  of  animals,  .either  in  the  form  of  the  skin 
or  of  the  wool,  which  is  made  into  cloth,  or  else  he  raises 
cotton  or  flax,  and  weaves  his  cloth  from  these  commodi- 
ties. In  the  early  development  of  this  country,  men  car- 
ried their  clothing  with  them  for  the  most  part.  Except 
in  case  of  great  need  they  made  use  of  the  skins  of  ani- 
mals only  for  certain  purposes,  such  as  the  making  of 
moccasins. 

Besides  the  need  for  food,  clothing,  and  shelter,  sup- 
plied in  part,  as  we  have  seen,  through  agricultural,  and 
in  part  through  the  natural  products  of  the  earth,  man 
needs  materials  for  giving  him  light  and  heat,  the  latter 
particularly  for  cooking,  and,  in  modern  times,  for  the 
creation  of  steam.  Formerly  heat  was  gotten  largely 
from  forests,  through  the  burning  of  the  wood,  and  thus 
homes  established  in  an  open  country  were  established 
under  difficulty.  Light  was  obtained  from  the  fat  of 
animals,  such  as  the  sheep,  or  later  from  oil  gathered 
from  the  whales.  At  present  a  large  supply  of  the  light 
and  heat  of  the  world  comes  from  the  deposits  of  coal, 
of  oil,  of  gas,  buried  in  the  depths  of  the  earth.  The 
mining  of  these  commodities  has  become,  as  we  have 
already  seen,  one  of  the  important  industries  of  the 
world,  and  the  distribution  of  these  several  things  has 
made  certain  parts  of  our  own  country  develop  with 
great  rapidity. 

Another  great  need  of  civilized  and  of  uncivilized  men 
is  materials  for  making  utensils  of  all  kinds  and  for 
implements  of  warfare.  Iron,  tin,  and  copper  have 
come  to  be  of  very  great  importance  to  modern  man ; 
but  in  the  early  time  it  was  the  presence  of  rocks, 
of  wood,  or  of  clay,  perhaps,  which  made  one  nation 


220  A   READER  IN   PHYSICAL  GEOGRAPHY. 

superior  to  another.  The  Indian  tribes  of  North  America 
that  occupied  a  region  containing  an  abundance  of  clay 
for  their  necessary  water-jars  and  other  cooking  utensils, 
and  plenty  of  rocks  of  the  proper  quality  to  make  arrow- 
heads and  spears,  had  a  great  advantage  over  their  neigh- 
bors, and  undoubtedly  profited  greatly  by  exchanging 
their  riches  with  their  neighboring  tribes,  getting  in  re- 
turn other  things  which  they  needed  but  could  not  make. 
An  arrow  or  spear  head  found,  at  the  present  time,  many 
miles  from  the  kind  of  rock  of  which  it  was  made,  is 
a  very  good  witness  of  trade  between  tribes  if  we  know 
from  other  reasons  that  the  two  regions  were  occupied 
by  different  peoples. 

In  modern  times  two  metals  have  come  to  be  of  very 
great  value,  partly  because  of  their  rarity  and  partly 
because  they  are  so  indestructible.  These  two  metals 
are  gold  and  silver,  of  which  the  larger  part  of  the  money 
used  in  trade  is  made.  The  seeking  of  these  metals, 
particularly  gold,  has  been  the  cause  of  the  settlement, 
and,  indeed,  of  the  discovery  of  the  valuable  features  of 
certain  countries.  It  was  gold  that  first  attracted  men 
to  California  in  1849;  but  many  of  the  settlers,  attracted 
first  by  the  gold,  remained  to  establish  one  of  the  great- 
est and  richest  States  of  the  Union,  having  found  other 
features  of  great  value. 

There  are  other  natural  products  to  be  gathered  from 
the  rocks,  in  the  primitive  forests,  or  from  the  wild  ani- 
mals, that  have  come  to  be  of  very  great  value,  although 
their  former  use  was  never  sufficiently  great  to  have  their 
presence  determine  the  rapid  development  of  a  region. 
We  find  good  illustrations  of  this  in  the  deposits  of  phos- 
phate in  Georgia  and  Florida,  which  are  now  being  ex- 
tensively used  for  fertilizers  in  farming,  but  which  once 


NATURAL  PRODUCTS.  221 

were  not  considered  worth  anything.  Among  other 
products  are  those  used  for  medicines,  like  the  bark  of 
the  cinchona  tree,  giving  us  our  quinine,  or  those  used 
for  more  general  purposes,  of  which  we  have  a  very  ex- 
cellent illustration  in  the  rubber  obtained  from  the  juice 
of  the  rubber  tree. 

With  the  development  of  peoples  new  uses  are  discov- 
ered for  commodities  once  wasted,  and  thus  new  reasons 
are  being  brought  forward  continually  for  the  develop- 
ment of  new  regions.  These  regions,  perhaps,  offer  no 
particular  advantages  for  civilization,  other  than  the  pres- 
ence of  some  particular  deposit  or  material,  like  those 
mentioned.  When  this  material  is  exhausted,  the  region 
will  again  be  deserted,  unless  some  other  advantages  of 
importance  be  later  discovered. 

A  knowledge  of  the  distribution  of  the  natural  prod- 
ucts of  the  earth,  and  sufficient  energy  to  secure  these 
products,  have  made  possible  the  commercial  progress  of 
certain  nations.  The  development  of  the  extensive  and 
widespread  colonies  of  Great  Britain,  for  instance,  has 
been  in  part  due  to  the  fact  that  the  English  have  been 
among  the  first  to  push  into  new  regions,  and  to  recog- 
nize the  value  of  the  natural  products  of  those  countries. 


CHAPTER   XXIII. 
TRANSPORTATION    AND   POWER. 

WE  have  already  seen  that  even  the  most  primitive 
people  are,  as  a  rule,  not  wholly  dependent  upon  them- 
selves and  their  own  locality  for  the  necessaries  of  life. 
When  any  people  have  more  of  any  valuable  commodity 
than  they  need,  and  lack  other  commodities,  it  is  very 
natural  that  trade  or  commerce  should  follow.  Early 
commerce  consisted  of  the  direct  exchange  of  one  ma- 
terial for  another,  as  one  boy  swaps  marbles  or  jack- 
knives  with  another.  As  trade  is  developed  among 
peoples,  the  need  of  some  indestructible  material,  like 
gold  and  silver,  that  should  stand  for  certain  wealth  has 
caused  barter  to  give  way  to  trade,  in  which  money  is 
used.  Trade  is  not  confined  any  longer  to  neighbors  in 
the  same  town  or  village,  but  takes  place  between  peo- 
ples and  nations  of  the  most  remote  parts  of  the  world. 
Trade  or  commerce  of  all  kinds,  therefore,  demands  the 
intermingling  of  peoples,  and  has  necessitated  ready 
means  of  transportation  over  the  lands  and  the  oceans. 
The  land  trails  of  the  Indian  traveller  and  hunter  gave 
way  to  the  road  later  occupied  by  the  stage  coach.  This 
in  turn  has  largely  been  replaced  by  the  railroads. 

In  each  case  the  line  of  communication  has  been  along 
the  most  accessible  route  that  makes  rapid  migration 
possible.  Natural  highways,  therefore,  such  as  the  Mo- 
hawk Valley,  already  mentioned,  have  come  to  be  the 
great  connecting  links  between  different  parts  of  the 


TRANSPORTATION  AND  POWER.  223 

country.  Canals  and  river  boats  have  again  followed  the 
natural  lines  of  commerce,  all  determined  by  the  geo- 
graphic conditions.  The  country  therefore  having  the 
best  facilities  for  the  development  of  railroads  and  canals, 
and  the  most  navigable  rivers,  has  the  best  chance  for 
sending  out  its  products  rapidly,  and  for  getting  in  re- 
turn, at  low  cost,  the  products  of  the  rest  of  the  world. 

The  world  commerce,  however,  demands  still  larger 
means  of  communication,  and  more  natural  conditions 
favorable  to  shipping.  Good  harbors  are  thus  an  essen- 
tial part  of  any  progressive  nation,  and  the  leading 
nations  of  the  world  are  continually  struggling  for  good 
harbors  in  the  different  parts  of  the  world.  The  recent 
success  of  Russia  in  securing  a  Pacific  harbor  on  the 
coast  of  China,  accompanied  as  it  has  been  by  the  build- 
ing of  a  railroad  across  Siberia,  has  enabled  Russia  to 
become  a  commercial  nation  of  great  importance.  Oce- 
anic routes  of  commerce;  between  good  harbors,  are 
very  largely  determined  in  their  direction  by  the  favor- 
able or  unfavorable  character  of  the  ocean  currents  and 
of  the  winds,  and  in  some  cases  by  the  presence  or  ab- 
sence of  floating  icebergs.  The  influence  of  ocean  cur- 
rents and  winds  is  interestingly  shown  by  the  fact  that 
sailing-vessels  from  Great  Britain  to  Australia  go  out  by 
way  of  Good  Hope  and  return  around  South  America 
and  Cape  Horn.  This  route  follows  the  direction  and 
the  course  of  the  southern  westerly  winds,  so  that  the 
vessels  have  favorable  winds  nearly  all  the  way  around 
the  world. 

While  trade  depends  very  largely  upon  favorable  geo« 
graphical  conditions,  there  are  other  aids  to  commerce, 
largely  the  result  of  inventions,  which  are  of  importance. 
The  establishment  of  beacons  and,  later,  of  government 


224  A   READER  IN   PHYSICAL   GEOGRAPHY. 

lighthouses  on  the  prominent  points  of  a  coast,  marking 
the  entrances  to  harbors  or  the  presence  of  a  dangerous 
coast,  very  naturally  followed  the  beginnings  of  trade. 
We  can  see  an  interesting  relic  of  the  former  burning  of 
a  beacon  to  guide  vessels  in  "  Beacon  Hill  "  in  Boston, 
on  which  is  situated  the  Massachusetts  State  House. 
This  hill,  in  the  centre  of  the  city,  was  formerly  the  site 
of  one  of  the  early  beacons  of  the  Atlantic  coast,  that 
shed  its  light  over  the  tops  of  the  houses  that  formed 
the  town  of  Boston,  and  out  over  the  waters  of  the 
bay  toward  the  sea. 

Associated  with  the  development  of  lighthouses,  which 
are  located  in  their  position  because  of  the  geographic 
features  that  make  the  coast  safe  or  unsafe,  we  have  the 
modern  establishment  of  government  life-saving  stations. 
These  stations  are  located  along  the  dangerous  portions 
of  our  coast  and  the  parts  passed  by  the  greatest  num- 
ber of  vessels,  the  object  of  the  life-saving  crews  being, 
of  course,  to  render  aid  to  any  vessel  in  distress.  Tele- 
graphs, telephones,  the  postal  system,  and  express  com- 
panies are  other  aids  of  commerce  that  have  all  developed 
as  commerce  has  developed,  and  that  make  it  possible 
for  men  to  take  advantage  more  promptly  of  the  natural 
conditions  about  them. 

Power. — The  success  of  a  people  or  a  nation  in  taking 
advantage  of  the  conditions  around  them  depends  very 
largely  also  upon  their  opportunity  and  ability  to  make 
use  of  other  power  than  that  of  their  own  hands  in  doing 
work.  As  a  result  of  the  desire  on  the  part  of  all  men 
to  save  themselves  labor,  we  find  the  increased  use  of 
animals  to  carry  burdens,  or  to  assist  in  the  transporta- 
tion of  goods  across  country.  The  Indian  warrior,  who 
must  ever  be  on  the  watch  for  the  game  that  will  give 


POWER.  225 

him  food,  keeps  himself,  as  a  rule,  perfectly  free  to  pur- 
sue his  game  at  all  times,  and  leaves  the  moving  of  the 
home,  the  gathering  of  the  wood  and  the  water,  and 
other  duties  of  a  similar  sort  to  the  women  of  the  tribe. 

Among  the  beasts  of  burden  that  are  most  used  are  the 
horse,  the  mule,  the  ox,  the  camel,  and  the  llama.  The 
horse  is  regarded  as  a  necessary  means  of  transportation 
by  almost  all  inhabitants  of  the  temperate  and  semi- 
tropical  regions,  and  is  used  very  generally  for  agricul- 
tural purposes  by  the  progressive  farmers  of  the  leading 
nations.  Where  speed  is  not  an  essential  quality,  we 
frequently  find  the  mule;  for  instance,  this  animal  is  used 
for  drawing  canal-boats,  which  cannot  be  moved  much 
above  a  certain  rate  per  hour.  In  some  places,  where 
great  strength  is  required,  we  find  the  still  more  slow- 
moving  ox ;  but  his  use  is  now  rapidly  declining  on  farms, 
because  a  successful  farmer  must  move  more  rapidly  than 
oxen  can  go.  At  present  the  special  field  for  oxen  in 
this  country  is,  perhaps,  in  lumbering  camps,  where  their 
ability  to  get  through  snow  and  to  move  heavy  loads  is 
of  particular  value. 

In  the  camel  of  the  eastern  deserts  we  have  an  animal 
particularly  serviceable  for  the  transportation  of  men  and 
of  burdens  across  the  arid  wastes  where  water  can  be 
secured  only  at  long  intervals.  The  supply  of  water 
which  he  carries  lasts  him  many  days;  his  soft-cushioned 
feet  enable  him  to  travel  with  ease  over  the  hot  sand. 
He  is  so  well  adapted  to  meet  the  conditions  of  the  des- 
ert, and  carries  such  heavy  burdens,  that  he  has  rightly 
received  the  name  of  the  "  ship  of  the  desert."  The 
llama  of  South  America,  though  smaller,  performs  a 
similar  service  for  the  travellers  in  the  rugged  highlands 
of  that  region. 
15 


226  A   READER  IN   PHYSICAL  GEOGRAPHY. 

With  the  development  of  machinery,  there  came  the 
desire  for  power  that  would  set  machinery  in  motion. 
In  certain  regions  we  find  horses  used  in  treadmills  to 
turn  machinery;  this  is  well  illustrated  in  the  threshing 
of  grain,  the  cutting  up  of  hay  and  of  corn-stalks,  and 
the  sawing  of  wood,  as  it  is  carried  on  on  many  eastern 
farms.  It  is  more  common,  however,  to  find  a  more 
powerful  agent  employed,  agents  which  are  not  animate 
and  do  not  tire.  The  most  natural  of  these  inanimate 
sources  of  power  is  that  of  falling  water,  which  is  still 
employed,  as  we  have  already  seen,  in  many  of  the 
cotton  mills  of  the  country.  Windmills,  which  are  used 
for  the  pumping  of  water,  are  frequently  employed  also 
for  running  farm  machinery;  but  the  supply  of  power  in 
the  case  of  the  wind  is  so  irregular  that  wind  power  is 
somewhat  unsatisfactory.  Steam  power  and  water  power 
are  so  superior  that  the  old-fashioned  windmills  once 
extensively  employed  in  New  England  for  the  grinding  of 
corn  are  no  longer  used,  and  have  practically  disappeared. 

The  greatest  of  all  sources  of  power  thus  far  used  is 
steam,  formed,  of  course,  by  the  heating  of  water  through 
the  burning  of  some  fuel  like  wood  or  coal.  The  possi- 
bilities of  the  use  of  steam  at  low  cost  depend  almost 
entirely  upon  the  ease  with  which  fuel  may  be  obtained. 
Most  of  the  great  factories  of  the  world,  and,  indeed,  the 
larger  number  of  the  smaller  industries  and  most  of  the 
railway  trains,  are  moved  by  steam  power.  The  newest 
of  the  forms  of  power  is  that  of  electricity.  This  is 
usually  secured  through  steam,  so  that  in  most  cases 
electricity  is  but  another  way  of  applying  energy  acquired 
from  the  burning  of  some  product.  The  advantage  of 
electricity  is  that  its  power  can  be  transported  long  dis- 
tances from  the  source  of  supply  without  serious  loss, 


POWER.  227 

as  we  see  illustrated  in  the  electric  car  lines  that  now 
cover  the  many  large  cities,  the  power  usually  being  sup- 
plied from  one  central  source.  A  power  house  has  recently 
been  established  at  Niagara  Falls,  New  York,  which  pro- 
duces a  tremendous  quantity  of ,  electrical  energy  from 
the  falling  of  the  water  diverted  from  the  falls.  This  is 
already  so  successful  that  electric  power  is  supplied  at 
moderate  cost  to  the  city  of  Buffalo,  twenty  miles  away. 
The  introduction  of  electricity  for  the  running  of  canal- 
boats  and  railway  trains,  as  well  as  street  railways,  means 
that  very  soon  not  only  manufacturing,  and  transporta- 
tion of  people,  but  an  increasing  amount  of  the  com- 
merce of  the  world,  will  depend  upon  the  right  use  of 
this  power.  It  should  be  noted,  also,  that  electricity  is 
coming  into  increasing  use  as  a  source  of  light  for  houses, 
railway  tunnels,  and  mines,  and  as  a  source  of  heat  for 
warming  buildings  and  cars,  and,  indeed,  for  cooking 
purposes. 


CHAPTER    XXIV. 
SUMMARY. 

SUCH  are  some  of  the  conditions  other  than  those 
of  climate  and  topography  that  determine  whether  a 
country  will  be  progressive  or  not.  It  should  be  re- 
membered, however,  as  we  have  already  suggested, 
that  not  every  country  in  the  world  with  good  climate, 
favorable  topography,  plenty  of  water,  abundant  natural 
products,  possibilities  for  commerce,  and  ready  access  to 
power  is  a  leading  nation.  Geographic  conditions  which 
we  have  mentioned  may  be  present,  and  yet  a  people 
may  make  less  progress  in  spite  of  its  opportunities  than 
other  people  lacking  some  of  these  opportunities.  Races 
of  men,  in  order  to  take  advantage  of  the  conditions 
about  them,  must  be  mentally  and  physically  able  to 
make  good  use  of  that  which  is  presented  to  them. 

The  Chinese  nation,  situated  practically  amid  the  same 
conditions  that  the  United  States  enjoys,  is  among  the 
most  unprogressive  nations  of  the  world;  it  should  be 
noted,  however,  that  China  has  been  far  removed  from  its 
most,  progressive  neighbors,  owing  to  the  great  land  bar- 
rier to  the  west  of  her  and  the  water  barrier  to  the  east. 
Primitive  peoples  are  much  more  dependent  upon  the  geo- 
graphic conditions  about  them  than  are  advanced  peoples, 
but  in  each  case  there  is  a  struggle  to  take  advantage  of 
the  favorable  conditions  and  to  overcome  the  unfavor- 
able. The  forms  of  shelter,  the  kinds  of  food,  the  char- 
acter of  the  clothing,  the  implements  of  the  household 


THE   HISTORICAL  DISTRIBUTION   OF  PEOPLES.      22Q 

and  the  chase,  vary  according  to  different  conditions 
under  which  people  live;  but  in  all  cases  they  are  used 
for  the  same  general  purposes.  No  individual  and  no 
nation,  however,  has  so  thoroughly  mastered  unfavorable 
natural  conditions  as  to  be  free  from  all  inconvenience 
because  of  them.  This  is  well  shown,  in  our  temperate 
regions,  by  our  constant  anxiety  about  the  weather  in 
planning  for  many  kinds  of  enterprises. 

The  Historical  Distribution  of  Peoples. — We  have 
already  seen  how  man  is  influenced  by  the  geographical 
conditions  about  him.  Let  us  look  for  a  moment  at 
some  of  the  great  nations  of  the  world,  and  see  how  they 
have  been  influenced  by  these  same  conditions.  In  the 
early  history  of  the  world  those  peoples  became  of  the 
greatest  power  who  early  found  their  home  amid  the 
most  favorable  conditions,  and  who  gradually  developed 
the  ability  to  go  out  into  new  regions  and  to  conquer 
them.  The  great  civilizations  of  the  Chinese,  the  Hin- 
dus, the  Persians,  the  Egyptians,  the  Greeks,  and  the 
Romans  were  developed  amid  conditions  that  were,  on 
the  whole,  favorable.  The  successful  ones  of  these 
nations  have  been  those  who  went  forth  into  new  coun- 
tries after  the  possibilities  of  their  own  had  been  ex- 
hausted. This  did  not  take  place,  however,  until  they 
had  developed  their  home  region. 

As  we  look  back  on  the  history  of  the  development  of 
civilization,  we  find  that  we  may  divide  the  history  of 
the  world  into  three  periods,  according  to  the  geographic 
conditions  amid  which  the  successful  nations  lived  at 
different  times.  These  three  divisions  are  the  earlier 
nations,  which  developed  in  the  rich  alluvial  plain  of 
some  great  river;  the  later  nations,  that  learned  the  ways 
of  commerce,  because  of  their  favorable  situation  for  such 


230  A   READER  IN   PHYSICAL   GEOGRAPHY. 

commerce  about  the  Mediterranean  Sea;  and,  finally, 
those  who  have  become  able  to  cross  the  oceans  more 
easily  than  the  land  and  to  whom  the  whole  world,  ex- 
cept certain  parts  that  are  ice-bound,  is  practically  free. 

The  Chinese,  who  developed  in  the  rich  and  fertile 
plains  of  the  great  Chinese  rivers;  the  Hindus,  who  grew 
to  great  power  amid  similar  conditions  about  the  Ganges; 
the  Persians,  in  the  valley  of  the  Euphrates;  and  the 
Egyptians,  in  the  eastern  portions  of  the  Sahara,  watered 
by  the  Nile,  are  excellent  examples  of  the  former  great 
nations  of  the  world,  who  developed  in  the  alluvial  plains 
of  rivers.  Later  we  find  the  powerful  nations  of  Greece 
and  Rome,  their  advantage  lying  in  the  fact  that  they 
were  situated  on  the  northern  and  temperate  shores  of 
the  Mediterranean  Sea,  along  an  irregular  coast,  which 
made  coastwise  commerce  possible.  Owing  to  the  abun- 
dant harbors  offered  by  this  irregular  coast,  the  fleets  of 
these  nations  were  given  a  much-needed  protection  in 
time  of  storms;  for  the  early  vessels  of  these  people  were 
either  manned  by  men,  or  if  propelled  by  sails  could  only 
sail  before  the  wind,  and  not  against  it.  The  presence  of 
great  numbers  of  harbors  was,  therefore,  a  very  valuable 
physical  feature  for  these  people.  After  their  success  in 
combating  the  winds  and  the  waves  of  the  Mediterranean, 
the  people  of  this  region,  like  the  Norse,  who  developed 
amid  similar  surroundings  on  the  irregular  coast  of  Nor- 
way, were  enabled  to  attempt  the  crossing  of  the  broad 
oceans. 

As  a  result,  we  have  the  discovery  of  the  Western 
Hemisphere,  followed  naturally  by  the  rapid  develop- 
ment of  world-wide  commerce.  The  early  nations  of  the 
world  were,  then,  river  or  alluvial  plain  nations,  and  mainly 
agricultural;  the  later  nations  were  Mediterranean,  and 


THE  HISTORICAL  DISTRIBUTION  OF  PEOPLES.      231 

among  them  commerce  was  developed.  Now  the  great 
oceans  are  no  longer  barriers,  and  we  are  living  in  an  age 
that  may  be  called  oceanic,  all  the  powerful  nations,  like 
the  United  States,  England,  and  Germany,  having  ready 
access  to  the  great  oceans,  and  making  free  use  of  them 
in  commerce  and  travel. 

The  influence  of  geography,  then,  can  be  seen  as  clearly 
in  the  study  of  the  history  of  a  great  nation  as  in  that  of 
a  city  or  town.  Great  numbers  of  people  are  collectively 
influenced  by  their  geographic  surroundings  in  the  same 
way  as  a  few  people  are.  Each  individual  in  a  town  may 
also  be  directly  influenced  by  the  geography  about  him. 
Thus  geography  is  important  to  the  many  as  well  as  to 
the  few,  and  a  study  of  the  world  peoples  must  be  accom- 
panied by  a  study  of  world  geography. 


INDEX. 


AGRICULTURE,  centres  of,  36,  37,  38, 
39,  40  ;  essentials  for,  36,  37;  im- 
portance to  man,  200  ;  soils  best 
for,  37. 

AIR,  5  ;  weight  of,  182,  185. 

ALLUVIAL  fans,  92,  93,  94  ;  rivers 
on,  94. 

ALLUVIAL  plains,  89,  90,  91,  92 ; 
cities  on,  91. 

ALTITUDE,  15,  17. 

ANTARCTIC  circle,  180. 

APPALACHIAN  Highlands,  21. 

ARCTIC  circle,  180. 

ARID  regions,  191,  192,  193. 

ARTESIAN  wells,  211,  212. 

ATMOSPHERE,  5  ;  work  of  the,  69,  70. 

BARS,  106. 

BAY,  ii. 

BEACHES,  n,  105,  106 ;  pocket,  105, 
106  ;  barrier,  107. 

BELTS,  heat,  effect  on  life,  180,  181, 
182,  183,  184,  194,  195,  197  ;  hot 
and  cold,  183  ;  of  calms,  185,  186  ; 
seasons  of,  195  ;  vegetation  of 
warm  and  cool,  195,  196,  197. 

BOILING  point,  176,  177. 

BOULDERS,  glacial,  133. 

BREEZES,  sea  and  land,  187,  188. 

CALMS,  Belt  of,  185,  186. 
CANCER,  Tropic  of,  179. 
CAPRICORN,  Tropic  of,  179. 
CARRY,  97. 

CENTRES  of  industry,  28,  29,  30,  31, 
32  ;  agricultural,  36,  37,  38,  39, 


40  ;  commercial,  33,  34,  35,  36  ; 
fishing  and  hunting,  53,  55  ;  graz- 
ing, 40,  41,  42,  43  ;  lumbering,  43, 
44,  45,  46  ;  manufacturing.  47,  48, 
49;  mining,  49,  50,  51,  52;  scenic, 
55,  56,  57  J  of  life,  30,  31,  32. 

CIRCLES,  180. 

CLIFF  dwellers,  215,  216. 

CLIMATE,  171  ;  for  agriculture,  37, 
38  ;  influence  of,  on  life  of  man, 
198,  199  ;  weather  and,  172,  173, 

174,  175- 

COAST  line,  II  ;  change  of,  166,  167, 
168  ;  features  of,  166. 

COASTAL  plain,  137,  138,  139. 

COLD  belts,  183. 

COMMERCE,  222,  223  ;  early,  222  ; 
oceanic  routes  of,  223  ;  relation  to 
harbors,  12  ;  world,  223. 

COMMERCIAL  centres,  33,  34,  35,  36  ; 
requirements  of,  33. 

CONTINENTAL  shelf,  138. 

CONTINENTS,  10  ;  drynessof  leeward 
side,  191  ;  features  of,  21  ;  mois- 
ture of  windward  side,  191. 

CORDILLERAS,  19,  20,  21. 

CRATER  LAKE,  Oregon,  160,  161  ; 
lakes,  160. 

CRATERS,  157,  158,  160  ;  kinds  of, 
158. 

CURRENTS,  influence  of  ocean,  182, 
223;  ocean,  108,  109,  no,  in, 
182  ;  use  of,  109,  no,  in. 

DEFENCE,  modes  of,  213,  214,  215, 
2,16,  217,  218. 


234 


INDEX. 


DELTAS,  94,  95,  96 ;  soils  of,  96. 
DEPOSITS,    glacial,    127,    128,    129, 

130,  131,  132  ;   of  running  water, 

88,  89  ;  wave,  IQI,   102,  103,  105, 

106. 

DESERTS,  191,  192,  193. 
DETRITUS,  68,  73,  74,  76,  86. 
DEW,  189. 
DISTRIBUTARIES,  95. 
DOLDRUMS,  186. 
DRAINAGE,  internal,  20. 
DRIFT,  109. 
DROWNED  region,  166,  167,  168,  169, 

170 ;    valleys,    168,    169 ;    Hudson 

river,  169,  170. 
DRUMLINS,  130,  131. 
DUNES,  77,  78,  79. 

EARTH,  8  ;  changes  in  the,  59,  60, 
61,  62  ;  forms  of  the,  59,  60  ;  heat, 
source  of,  177,  178;  motions  of 
the,  178,  179,  180  ;  wearing  away 
of  the,  67,  68. 

EARTHQUAKES,  163,  164. 

EARTH'S  crust,  materials  of  the,  62, 
63,  64,  65. 

EQUATOR,  climate  at  the,  182  ;  heat, 
184. 

EROSION,  65,  68,  82  ;  river,  82,  83, 
84,  85,  86  ;  wave,  101,  102,  103, 
104 ;  wind,  76,  77  ;  work  of  ice, 
125,  126,  127. 

ESKIMO,  3,  28. 

FANS,  alluvial,  92,  93,  94. 

FARMING,  37,  38. 

FISHING  and  hunting  centres,  53,  55. 

FORESTS,  44.  45,  50. 

FORTS,  216,  217. 

FREEZING  point,  176,  177,  183. 

FROST,  effect  on  life,  119,  120;  effect 


on   rocks,    120,    121  ;   work  of  ice 
and,  119,  120. 

GEOGRAPHIC  position,  influence  of 
on  nations,  229,  230,  231. 

GEOGRAPHICAL  conditions,  influence 
upon  life,  I,  2,  3,  4  ;  importance 
of,  57,  58. 

GEOGRAPHY,  practical  value  of,  i  ; 
home,  3. 

GEYSERS,  164. 

GLACIERS,  121,  122,  123,  124,  125, 
126,  127  ;  carrying  power  of,  133  •, 
continental,  125  ;  valley,  125. 

GLENS,  15. 

GOLD,  220. 

GRANITE,  64. 

GRAVITY,  73,  74,  81 ;  effect  of,  73. 

GRAZING  centres,  40,  41,  42,  43. 

GREAT  Basin,  20. 

GREAT  Lakes,  115. 

GREAT  Salt  Lake,  20,  114. 

GULFS,  II. 

GULF  Stream,  109,  no. 

HAILSTONES,  189. 

HARBORS,  108,  170  ;  New  York,  34. 

HEADLANDS,  104,  105,  106. 

HEAT,  rays  of,  178  ;  source  of  earth, 
177,  178. 

HEAT  belts,  180,  181,  182,  183,  184; 
effect  on  life,  194,  195,  196,  197  ; 
equator,  184. 

HEMISPHERES,  180. 

HIGHLANDS,  14,  15,  18,  21  ;  Appa- 
lachian, 21 ;  Cordilleran,  19,  20,  21; 
effect  on  rainfall,  190,  191  ;  of 
Scotland,  15  ;  unfavorable  to  occu- 
pation, 22,  199. 

HISTORICAL  distribution  of  peoples, 
229,  230,  21. 


INDEX. 


235 


HORSE  latitudes,  186. 

HOT  springs,  164. 

HUDSON  river,  drowned,  169,  170. 

HUNTING  centres,  fishing  and,  53,  55. 

ICE  and  frost,  effect  on  life,  119,  120  ; 

effect  on  rocks,  120,  121  ;  work  of, 

119,  120. 
ICE,  erosive  work  of,  125,  126,  127  ; 

transportation  work  of,  126,  127. 
ICE  sheet,  great,  125  ;  work  of  the, 

132,  133. 

ICEBERGS,  123,  124. 
INDIANS,  i,  3,  44,  214. 
INDUSTRY,  centres  of,  28,  29,  30,  31, 

32  ;  development  of,  35. 
IRON,  49,  219. 
IRRIGATION,  39,  204,  207  ;  effect  of, 

207. 

ISLANDS,  10,  108,  167,  168. 
ISLAND  tying,  108. 
ISOTHERMS,  184. 
ISTHMUS,  108. 

LABRADOR  current,  no. 

LAGOON,  107. 

LAKE  dwellers,  216;  floors,  116. 

LAKES,  113,  114,  115,  116;  crater, 
160,  161  ;  Great,  115  ;  importance 
of,  114,  115,  116  ;  influence  of, 
114,  115,  116. 

LAND,  4,  5,  13  ;  breezes,  187  ;  dis- 
tribution of,  ii  ;  forms,  larger, 
137  ;  forms  of,  59,  60,  61,  62  ;  heat 
absorbed  by  the,  181  ;  movements 
of  the,  165,  166. 

LATITUDES,  Horse,  186. 

LAVA,   154,   155,   156,    158  ;   plains, 

159- 

LIFE,  centres  of,  30,  31,  32  ;  controls 
of,  198,  199 ;  saving  stations,  224. 


LIGHTHOUSES,  104,  224. 
LIMESTONE,  64. 
LOAD,  84,  85. 
LOESS,  80,  202. 

LOWLANDS,   15,  21,   22,  23  ;   favor- 
able to  occupation,  22,  23,  199,  200. 
LUMBERING  centres,  43,  44,  45,  46. 

MACHINERY,  226. 

MANHATTAN  Island,  50. 

MANUFACTURING,  98 ;  centres,  47, 
48,  49. 

MAPS,  wall,  13,  14  ;  use  of,  9. 

MARTINIQUE,  155. 

MEDITERRANEAN  people,  230. 

MINING,  6,  153  ;  centres,  49,  50,  51, 
52. 

MOISTURE,  70,  71,  174,  175,  188, 
189,  190 ;  and  rainfall,  188  ;  effect 
of,  189,  190  ;  source  of,  190  ;  tak- 
ing winds,  192. 

MONADNOCKS,  152. 

MONT  PELEE,  156. 

MORAINES,  128,  129. 

MOTIONS  of  the  earth,  178,  179,  180. 

MOUNTAIN  mass,  18  ;  peak,  18  ;  sys- 
tems, 19,  20,  21. 

MOUNTAINS,  15,  16,  17,  18,  144,  145, 
146  ;  aging  of,  150,  151,  152,  153  ; 
block,  150 ;  building,  147,  148 ; 
causes  of,  148,  149  ;  domed,  150 ; 
effect  on  rainfall,  190  ;  folded,  149  ; 
height,  18  ;  kinds  of,  149,  150. 

NATIONS  of  the  world,  229,  230,  231. 
NATURAL  products,   218,   219,   220, 

221. 
NEW  YORK,   30,   34 ;    Greater,   23  ; 

physical  features  of,  23,  24,  25,  26^ 

27. 
NORTH  AMERICA,  19,  20,  21. 


236 


INDEX. 


OCEAN,  5,  6,  10;  currents,  108,  109, 
no,  in,  182  ;  currents,  influence 
of,  182,  223. 

OCEANIC  people,  231. 

OVENS,  104. 

PENEPLAIN,  151,  152. 
PENINSULA,  108,  167,  168. 
PEOPLE,    historical    distribution   of, 

229,  230,  231;  Mediterranean,  230; 

oceanic,  231  ;  river,  230. 
PIEDMONT,  151. 
PLAIN,  14,   139,   140,  141  ;  Atlantic 

Coastal,  21,  137,  138,   139  ;    Great 

Central,  21,  141. 
PLAINS,  137,  138,  139,  140, 141  ;  age 

of,  139,  140  ;  alluvial,  89,   90,  91, 

92  ;  lava,  160. 

PLATEAU,  14  ;  Alleghany,  142  ;  Colo- 
rado, 141  ;  Cumberland,  141,  142, 

143- 

PLATEAUS,  141,  142,  143. 
POCKET  beaches,  105,  106. 
POWER,  sources  of,  47,  225,  226,  227  ; 

steam,  47,  48  ;  water,  47,  48. 
PRESSURE,  173,  185. 
PREVAILING  winds,  region  of,  186, 

187. 
PRODUCTS,  exchange  of,  29. 

QUARRIES,  49,  50. 

RAIN,  189. 

RAINFALL,  causes  of,  190  ;  effect  of 
highlands  on,  190,  191  ;  effect  of 
mountains  on,  190  ;  moisture  and, 
188,  189,  190,  191  ;  of  world,  192, 

193- 

RAPIDS,  96,  97,  98. 
RELIEF,  15,  16,  17. 
RESERVOIRS,  114,  212. 


RIDGE  makers,  65,  66. 

RIVER,  82,  83,  84,  85,  86,  88,  89; 
valley,  82  ;  distributaries,  95  ;  sys- 
tems, 19,  20  ;  tributaries,  95. 

ROARING  forties,  186. 

ROCKING  stone,  128. 

ROCKS,  62,  63,  64,  65,  66,  67,  68  ; 
crystalline,  63,  64  ;  effect  of  ice  and 
frost  on,  120,  121  ;  igneous,  65  ; 
plutonic,  64  ;  stratified,  63  ;  strong 
and  weak,  65,  66;  volcanic,  64, 
65. 

RUNNING  water,  deposits  of,  88,  89  ; 
erosive  work  of,  82,  83,  84,  85,  86  ; 
results  of,  98,  99  ;  work  of,  81,  82. 

ST.  VINCENT,  155. 

SANDSTONE,  64. 

SAVANNAS,  195. 

SCENIC  centres,  55,  56,  57. 

SCOTLAND,  Highlands  of,  15. 

SCOUR,  tidal,  112,  113. 

SEA  breezes,  187. 

SEA  level,  10. 

SEA  ports,  34. 

SEAS,  10. 

SEASHORE,  u. 

SEASONS,  194. 

SHADOW,  177,  178. 

SHORE  line,  n,  12  ;  irregular,  12, 
104;  regular,  n  ;  relation  of  com- 
merce to,  n. 

SLATE,  64. 

SLEET,  189. 

SLOPES,  200  ;  for  agriculture,  36,  37  ; 
talus,  74,  75. 

SNOW,  119,  120,  121,  189  ;  line,  145, 
146. 

SOIL,  37,  38,  39 ;  imoortance  of, 
200,  201  ;  fertility  of,  204,  205  ; 
kinds  of,  201,  202,  203. 


INDEX. 


237 


SPRINGS,  6,  207,  208,  209 ;  hot,  164. 
STANDING  water,  effect  of,  116,  117, 

118  ;  importance  of,  116, 117,  118  ; 

work  of,  100,  101. 
STEAM,  188,  226. 
STREAMS,    glacial,    123,    131,    132  ; 

lengthening  of,  84. 
SUN,  movement  of  earth  around  the, 

179- 

SYSTEMS,  mountain,  19,  20,  21  ;  riv- 
er, 19,  20 ;  wind,  186,  187. 

TALUS  slopes,  74,  75. 

TEMPERATURE,  172,  173,  176,  177, 
181,  183,  184 ;  measurement  of, 
176, 177  ;  effect  of  altitude  on,  182, 

183- 

THERMOMETER,  176  ;  Fahrenheit, 
176. 

TIDAL  scour,  112,  113. 

TIDES,  in,  112,  113  ;  cause  of,  112  ; 
work  of,  112,  113. 

TILL,  129,  130. 

TOPOGRAPHY,  41,  57,  59,  60 ;  in- 
fluence on  life  of  man,  199,  200. 

TRADE  winds,  185  ;  belt,  190. 

TRANSPORTATION,  need  of,  222,  223. 

TRIBUTARIES,  95. 

TROPICS,  179  ;  life  in,  28  ;  Cancer, 
179;  Capricorn,  179. 

UNDERTOW,  103. 

UNITED  STATES,  rainy  portion  of, 
190. 

VALLEY,   river,    82 ;  drowned,    168, 

169,  170. 

VOLCANO,  throat  of,  157. 
VOLCANOES,  154,  155,  156,  157.  158. 

159,  160,  161,  162,  169;  aging  of 


159,  160,  161,  162  ;  kinds  of,  158, 
159;  shape  of,  156,  157. 
VOLCANIC  countries,  158,  159;  necks, 
162. 

WATER,  5  ;  distribution  of,  10,  n  ; 
erosion  by,  67,  68  ;  heat  absorbed 
by,  181  ;  running,  81,  82  :  stand- 
ing, 100,  101  ;  effect  cf  standing, 
116,  117, 118  ;  importance  of  stand- 
ing, 116,  117,  118  ;  supply,  206, 
207  ;  underground,  6,  207,  208, 
209,  210,  211,  212  ;  use  of  falling, 
226. 

WATERFALLS,  96,  97,  98. 

WAVE  deposits,  101,  102,  103,  104, 
105,  106,  107  ;  erosion,  101,  102, 
103,  104. 

WEATHER,  172,  173,  174,  175  ;  and 
climate,  172,  173,  174,  175  ;  influ- 
ence of,  5,  6. 

WEATHERING,  69,  70,  71,  72,  73. 

WELLS,  207,  209,  211,  212  ;  artesian, 

211,  212. 

WESTERLY  winds,  186,  187. 

WIND,  173,  174;  erosive  work  of, 
76,  77  ;  power,  226  ;  systems,  186, 
187. 

WINDS,  causes  of,  185,  186,  187 ; 
desert,  191,  192  ;  direction  of ,  187, 
188  ;  effect  of,  192  ;  moisture  tak- 
ing, 192 ;  regions  of  prevailing, 
186,  187 ;  trade,  185  ;  westerly, 
186,  187. 

WORK,  importance  of,  28. 

WORLD,  as  a  whole,  4,  5,  6  ;  compo- 
sition of  the,  4,  5,  6,  7  ;  inter- 
mingling of  parts,  6,  7,  8. 

ZONES,  180,  183. 


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